Learn how to make perfectly thin and crispy chocolate chip cookies. The science of the chocolate chip cookie is explored to create your perfect cookie! 

Thin and Crispy Chocolate Chip Cookies on a marble slab

All chocolate chip cookies are not created equal. And everyone’s preference for the perfect chocolate chip cookies are definitely not the same.

I posted what I call The Best Chocolate Chip Cookies a while back. In my mind nothing could top them. Crispy on the outside, thick and chewy on the inside. Loaded with dark chocolate and toasted pecans and a decent amount of salt. I am salivating just typing these words. But everyone has their own vision of what creates a perfect cookie. That is what this week is all about!

If you were around yesterday then you already know that I declared this week Chocolate Chip Cookie week! If you weren’t around yesterday then you might want to peruse this post. It’s about math. But math that leads us to cookies. So just suck it up for a moment. Then come back here! Because here is where the cookies are!

The side view of a Thin and Crispy Chocolate Chip Cookie

You see that? That up ^ there. That is one thin and crispy cookie! That isn’t just an accident. That takes some knowledge and skill about baking science and math to purposefully do that.

Here’s the rundown:

When a cookie spreads during baking the thinner and crunchier the baked cookie will become. Fat plays an important role in promoting spread of a cookie. A high fat content, and specifically a high butter fat content, will promote spreading. Butter melts at a lower temperature than other fats such as shortening. This promotes faster spreading and prevents the cookie from setting before it becomes flat.

Sugar is equally as important in this thin and crispy game. Sugar begins to liquefy during baking and helps increase spread. However, not all sugar is created equal.

Granulated sugar is going to create a more crispy cookie than cookies with brown sugar. In culinary school we talked a lot about sugar being hygroscopic, meaning that it absorbs water. Granulated sugar is the least hygroscopic of other sugars used in baking. It therefore leaves more moisture in the batter that will then evaporate when baked.

We also can’t forget the makeup technique when trying to produce these thin and crispy gems. It is important that the butter and sugar are well creamed in the first step of mixing. This aerates the batter and increases spread.

It is equally important not to mix too much once the flour is added. You don’t want to overdevelop glutens. This will decrease spread because it creates a more stable structure, which is not desirable in this circumstance.

Baking time and temp are also important to note. This isn’t the kind of cookie that we can go underbaked on. It just doesn’t work for crispy. You want a moderately high temp, but not too high. 350F should do the trick. It will allow for the cookie to spread sufficiently before setting, and a longer baking time will ensure the cookie is baked all the way through and will produce a crispy product.

Thin and Crispy Chocolate Chip Cookies on a marble slab

Am I making your head hurt yet? Hopefully not too much!

I want to use baker’s percentages to look at this thin and crispy recipe. If you remember from yesterday, when using baker’s percentages the amount of flour in the recipe is always 100%, not matter how much. The rest of the ingredients are then calculated based off the amount of flour to determine their relative percentage. Again, check out yesterday’s post if you are a little lost here.

The basic formula for finding baker’s percentages is:
weight of ingredient/ (divided by) weight of flour x (multiplied by) 100= baker’s percentage

So when looking at the recipe below to determine the percentage for the granulated sugar you take
248/286=0.86 X 100= 86%

1 1/4 cup (8.75 oz, 248 gr) granulated sugar- 86%
1/4 cup (1.8 oz, 53 gr) brown sugar- 18%
2 sticks (8 oz, 227 gr) unsalted butter- 79%
1 (1.8 oz, 51 gr) large egg- 17%
1 TBSP (0.5 oz, 14 gr) vanilla- 5%
1 tsp (0.2 oz, 5 gr) kosher salt- 2%
1 tsp (7 gr) baking soda- 2.5%
2 1/4 cup (10.1 oz, 286 gr) all purpose flour 100%

When you look at these numbers a few things jump out. The sugar ratio to flour is relatively high. When you add both sugars together you have 104% and a large majority of that is granulated sugar which, as we talked about, will retain less moisture creating a crispy cookie.

The butter percentage is also high. This will increase our spread and allow more surface area to create crispness.

The moisture content is also very low. Really the only moisture in the recipe is from the egg and the vanilla, and a little bit in the butter. Less moisture keeps a cookie more crisp. All of this combined with the makeup that will be in the recipe instructions below should produce a very thin and crispy cookie.

It’s science! The best kind of science. Cookie science!

Thin and Crispy Chocolate Chip Cookies stacked up

Thin and Crispy Chocolate Chip Cookies on a marble slab
Yield: 24 Cookies

Thin and Crispy Chocolate Chip Cookies

Prep Time 15 minutes
Cook Time 18 minutes
Total Time 33 minutes


  • 1 1/4 cup (245 gr) granulated sugar
  • 1/4 cup (56 gr) brown sugar
  • 2 sticks (227 gr) unsalted butter
  • 1 large egg
  • 1 TBSP (14 gr) vanilla
  • 1 tsp (5 gr) kosher salt
  • 1 tsp (7 gr) baking soda
  • 2 1/4 cup (270 gr) all purpose flour
  • 2 cups (340 gr) chocolate chips of your choice (I use dark chocolate)


Note: There are a few things that are important for making these cookies turn out very flat and crispy. Make sure you measure your flour properly by lightly spooning it into your measuring cup without packing it down at all and then level it off (or better yet, measure by weight!). It is also important that your oven is not too hot or the cookies will set before they have time to spread. If you think your oven heats hotter than its set temperature, turn the temperature down to 325 F and bake for several minutes longer. You also want to make these into very large cookie mounds so that they will spread out completely and get crispy.

  1. Preheat oven to 350F (177 C). Set a rack in the middle position in your oven.
  2. In the bowl of a stand mixer fit with a paddle attachment, or a large bowl with a hand mixer, cream the butter with the granulated sugar and brown sugar on medium high speed. Cream for a full 5 minutes, until light and fluffy, scraping down the bowl periodically throughout. This amount of creaming time will ensure your cookies will spread. Reduce the speed and add the egg and the vanilla and mix until well combined.
  3. Sift together the flour, salt, and baking soda in a separate mixing bowl.
  4. Slowly add the flour mixture to the butter mixture, scraping the sides of the bowl until thoroughly combined. Mix just until combined, do not overmix! Stir in the chocolate chips.
  5. Scoop large mounds of dough (about 3 TBSP each, the size is important) onto baking sheets lined with parchment paper or a silpat. It is best to only scoop about 9 cookies per sheet to allow enough room for spreading.
  6. Bake one cookie sheet at a time on the center rack of the oven at 350 F (177 C) for 15-18 minutes, rotating the pan halfway through.
  7. Remove cookies from baking sheet onto a cooling rack to cool completely.

Nutrition Information:

Amount Per Serving: Calories: 247