The Science of The Chocolate Chip Cookie

Baker Bettie Baking Science, Cookies, Holiday, Sweets 158 Comments

Learn the science behind making chocolate chip cookies! This post goes in depth about how to make recipe substitutions to make your perfect cookies as well as a recipe for thin and perfectly soft & chewy chocolate chip cookies! 



There is no doubt in my mind that Chocolate Chip Cookies are the ultimate classic baked good and comfort food.  There is just nothing that compares to a warm gooey cookie right out of the oven.  And a few years ago I set out on a mission to develop the most perfect chocolate chip cookie recipe ever.  But this led to the question: What is my idea of the perfect chocolate chip cookie?  Well, I am all about contrasts.  So in my mind it needs lots of contrasts of textures and flavors.  And I created that for myself.  A thick, chewy on the inside crunchy on the outside cookie that has hints of caramel and salt with dark chocolate chips and toasted pecans.

I had the brilliant idea for customizable cookies according other people’s idea of a perfect chocolate chip cookie.  Thin and crispy with milk chocolate?  Cakey and puffy with peanut butter, cinnamon and dark chocolate? Whatever your little heart desired.  I became obsessed with the science of the cookie.


The other day somehow this topic came up with a co-worker of mine.  She told me she had been trying to make really thin, chewy cookies for some time now with little success.  Open the flood gates! My mind started racing trying to remember all of the things I researched about the science of baking and I immediately started using my formula to create this recipe.

For any other geeks out there that are as interested in the science of baking as I am, I introduce to you “Baker Bettie’s Rules for Customizable Chocolate Chip Cookies!”

We will start with the standard Nestle Tollhouse Cookie Recipe: 

  • 2 1/4 cups all-purpose flour
  • 1 tsp baking soda
  • 1 tsp salt
  • 1 cup butter, softened
  • 3/4 cup granulated sugar
  • 3/4 cup packed brown sugar
  • 1 tsp vanilla
  • 2 large eggs
  • 2 cups Nestle Toll House Chocolate Chips
You know the drill: Combine dry ingredients.  Cream butter and sugar.  Add the other wet ingredients.  Add the dry ingredients to the wet and the chips.  Bake in a 375 degree oven for 9-11 minutes.
This recipe creates a fairly standard cookie.  Slightly chewy, slightly crunchy. Not too flat, not too caky.  Fairly neutral.  So to create the kind of cookie you are looking for, you can manipulate each component of this recipe.

Flour: If you want a chewier cookie change out the all-purpose flour for bread flour.  Bread flour has more protein and therefore will create more gluten.  If you want a taller cookie with a lot of texture cut back the flour to 2 cups and add 1 cup of oatmeal flour.  You can find this in the grocery store or create your own by grinding old fashioned oats in a blender to a fine crumb.


Baking Soda/Powder: There is no baking powder in the original recipe but if you want taller and cakey cookies add 1 tsp.  Keep the 1 tsp baking soda. to learn more details about baking soda and baking powder and how to sub or eliminate them, check out this post. 

Salt: Salt is one of the ingredients that only affects the flavor.  You can reduce or increase this amount according to your own preference for the salty/sweet combo.  But don’t eliminate it completely! I usually increase it to 1 1/4 tsp and use kosher salt for a more coarse flake.

Butter: There are several things you do with the butter.  If you are wanting a nice chew to the cookie and have decided to opt for the bread flour, melt the butter.  The water from the melted butter will mix with the flour to create more gluten.  (I learned this from Alton Brown)  If you like a more complex caramel flavor to your cookie, brown the butter.  If you want a taller, cakey cookie, use shortening instead of butter.  You can use butter flavored shortening if you want to keep the butter taste, but some people prefer the flavor or regular shortening.  Shortening will also make a very soft cookie.

Sugar: The ratios of the white sugar to brown sugar are important to produce the kind of cookie you want.  Higher white sugar to brown sugar ratios will produce a more crisp and crunchy cookie while higher brown sugar to white sugar ratios will produce a more soft and chewy cookie.  Dark brown sugar will up the chewiness even more.  Play around with it to produce the texture you want!

Vanilla: Vanilla only affects the flavor.  Increase the amount up to 1 tbsp if you really like the flavor, or eliminate all together if you want a more buttery flavor.  You can also use mexican vanilla for a more unique flavor.  It almost has hints of cinnamon.

Eggs: Eggs puff baked goods so eliminate an egg if you want a flat cookie and keep both eggs if you want a taller cookie. Egg whites dry out baked goods so if you like a really crunchy cookie add another egg white.  Alternatively, if you prefer a moist chewy cookie eliminate one egg white or one egg altogether.  You can even add a little bit of milk to add more moisture in place of the egg.

Add Ins: This is where you get to let your creativity go.  When I offered my customized chocolate chip cookies for my business you had these options: milk chocolate chips, dark chocolate chips, bittersweet chips, butterscotch chips, white chocolate chips, peanut butter, cinnamon, oatmeal, cocoa powder (to make the whole cookie chocolate), cayenne, toasted pecans, toasted walnuts, raisins, orange zest, dried cranberries, and toasted coconut.


Other Tips: Higher cooking temps (375) will keep a cookie taller while a lower temp (325 or 350) will allow the cookies spread out more.  Chilled dough will also produce a taller cookie.  If you like really soft cookies, spray them with a bit of water before baking.

Things I Never Change: Always bake your cookies in small batches to produce even browning.  (I cook 6 at a time)  Always bake on foil or parchment paper so you can immediately slide the cookies off the baking sheet when they come out of the oven.  This way the hot pan won’t continue to cook the cookies.  Remove from the oven just when the edges are brown and not when the entire cookie looks cooked through.  They will be over cooked.  If at all possible, always rest the dough for at least an hour or overnight before baking.  This will give you a more evenly cooked cookie.  And ALWAYS use a scoop!


So using the rules stated above, I came up with a recipe for a thin and chewy cookie.  They were perfect.


What is your perfect chocolate chip cookie like?


Thin and Chewy Chocolate Chip Cookies

Thin and Chewy Chocolate Chip Cookies


  • 2¼ cups bread flour
  • 1 tsp baking soda
  • 1¼ tsp kosher salt
  • 2 sticks unsalted butter, melted
  • ¼ cup granulated sugar
  • 1½ cup dark brown sugar
  • 1 egg
  • 2 tbsp milk
  • 1 tbsp vanilla
  • 2 cups chocolate chips


  1. Combine the bread flour, baking soda, and salt in a medium bowl.
  2. Melt the butter slowly and Add to the bowl of a stand mixer fitted with a paddle attachment.
  3. Beat the butter, granulated sugar, and dark brown sugar until combined.
  4. Add the egg, milk and the vanilla and beat on medium slow speed until incorporated.
  5. With the mixer on low speed, gradually add the dry ingredients into the wet ingredients until all incorporated.
  6. Scrape down the bowl as needed.
  7. Add in the chocolate chips and mix until incorporated.
  8. Allow to rest for 1 hour.
  9. Preheat the oven to 350 degrees.
  10. Line baking sheets with foil or parchment paper.
  11. Using a large scoop, drop 6 dough balls onto each cookie sheet.
  12. Bake for 11-14 minutes, just until the edges are lightly browned.
  13. Slide the cookies on the foil or parchment off the cookies sheet as soon as they come out of the oven.
  14. The cookies will be just slightly crunchy on the edges when cooled. If you want a completely chewy cookie and can resist eating them right away, store in an airtight container overnight and the cookies will be very chewy and soft in the morning.

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Baker BettieThe Science of The Chocolate Chip Cookie

Comments 158

  1. Bela Sziklassy


    These are the cookies of my dreams I had been waiting for. A light crunch, chewy but not too much so. These are heaven. But I guess heaven comes at a price. This recipe made about 18 cookies. 2 sticks of butter divided by 18 cookies is… a mess of a lot of butter per cookie. I had to give a dozen away, else I would have eaten them all. But seriously. This recipe can win awards.

  2. E

    These cookies are AMAZING! I made them yesterday and found that they were the best chocolate chip cookies I ever made! I am saving this recipe!

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  5. Watson

    I make the best chocolate chip cookies that anyone I’ve fed them to has tasted, but mostly what I mess with is the flavorings, not the flour, sugar, etc. I use the standard joy of cooking chocolate chip cookie recipe with the following alterations:

    add ~1 tsp of cinnamon
    replace 1 1/2 tsp vanilla with 1 tsp vanilla and 1/2 tsp almond extract
    use AT LEAST 2 cups of chocolate chips

    It’s really simple but the results are amazing.

  6. Demara Dawn Wig

    …I followed your Thin and Chewy Chocolate Chips recipe to the letter (..with the exception of using margarine instead of butter, and 2 1/2 tsp baking powder instead of baking soda (..according to your ""..) and they did not flatten at all and sort of burned on the bottom..!! I am perplexed. :( I thought I had finally found the perfect 'flat and chewy' cookie. I will have to try again, and follow exactly… But would margarine instead of butter, or powder instead of soda change it that much..?? ..Or, make it not change.. They looked exactly like how I put them in! Still tastes SO GOOD, but I want them flat..!! ..Ideas..??

    1. Post
      Baker Bettie

      Yes! These changes would change it a lot actually! Margarine has a higher melting point than butter. When the butter melts it helps the cookie spread. With margarine the cookie will likely set before it has a chance to spread. Margarine also typically has less fat content than butter and this could lead to the burning. It is also possible that your oven is cooking too hot, which is a common problem. You could try turning it down 25ºF and see if that helps. Are you using a baking sheet that has a dark coating? That could also lead to problems.

      The substitution for the baking powder and baking soda information I posted in that post is really meant for a pinch situation. If you are wanting specific results you really can’t substitute the two. They are very different things. Substituting or leaving out will always change the results.

      My idea really is just to try the recipe as written. And possibly turning down your oven temp.

  7. Paulette

    Love this blog. Makes baking so interesting and fun. This chocolate chip recipe is the best ever, perfect every time. One thing I do is to use coconut palm sugar to replace the white and brown sugars. I use the same total amount and the cookies are still perfect every time. Thanks for this wonderful, fun blog.

  8. porkchop man

    Love love love them! ! I have been tring a lot of recipes about 10.. befor I found this one just what I wanted thanks a lot 8)

  9. Nathan Jean

    Seems like no matter what I try. My cookies end up puffing up in the oven instead of melting flat. I want flat cookies! Not these little mounds. I followed this to the T too.

  10. Maria Jeryes ELshayeb

    okay I have 2 Q.
    1. you said to let it rest for an 1 hour. do I let if rest in the fridge or outside? and if i let it rest in the fridge do I let it warm when i take it out?
    2. how may cookies dose it make?

    1. Post
      Baker Bettie

      The dough should rest in the refrigerator and no, you do not need to let it come to room temp. The chilled dough will bake more evenly. It really depends on how big you make your cookies, but this should yield 2 dozen large cookies or 4 dozen small cookies.

  11. BakerBettie

    This could be an elevation issue. Do you live at a high elevation? This could also be too much flour in your batter. How do you measure your flour? You want to fluff it up with a spoon or fork and very lightly spoon it into the measuring cups without packing it down. Then level it off with a knife. If you have a kitchen scale, that would even more more accurate. 1 cup of flour should weigh 4.5 oz. So for this recipe you need 10.1oz. Also, are you making sure to cream your butter and sugar well? I will edit the recipe to reflect this, but you want to cream it together for about a minute. The little bit of air incorporated into the batter here will help it spread. Hopefully this helps!

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  13. Maria Eveliina Tuomela

    These cookies turned out absolutely perfect! I've been trying out more recipes than I can count, and this one gave by far the best results. The dough did turn out quite liquidy but it hardened to a nice consistency after I refrigerated it for a while.

  14. Charlie B.

    I made these today and they were ok. They didn’t really flatten out (even though I followed the recipe) so I flattened them out myself. Taste wise they were kinda bland, almost like something was missing but the texture was nice. I think that next time when I make these I’ll add more vanilla and maybe some spices like cinnamon but overall these were ok.

  15. heather

    These cookies are fabulous right out of the oven! However, mine hardened a little more than I like by the next morning. Any idea as to why?

    1. Post
      Baker Bettie

      How did you store the cookies Heather? They are best stored in an airtight container. It will trap the moisture in and keep them soft. It also sounds like the cookies may have been a bit over baked.

  16. Johanna

    I found that flattening the batter before baking yielded flatter cookies than just leaving the batter in mounds. I like my cookies flat not cakey, crispy edges, chewy centre, caramel flavour with a hint of salt. :)

  17. janine

    I was wondering after I placed them on the sheet if I could just leave them in the fridge overnight so I can bake them in the morning?

  18. janine

    I was wondering after I placed them on the sheet if I could just leave them in the fridge overnight so I can bake them in the morning?

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