Creme mousseline, aka German buttercream, is a style of frosting and pastry filling that is made with a custard base that is beaten into butter. It is pale yellow in color, is very soft and fluffy, and slightly sweet. 

Creme Mousseline (German Buttercream) Recipe Overview

  • Skill Level: Intermediate
  • Techniques Used: Making a Custard
  • Characteristics: Pale yellow in color due to using whole eggs, softer than meringue buttercreams or american buttercreams, does not hold up well in hot temperatures, lightly sweet in flavor, very silky smooth, tastes like a custard

What is German Buttercream? 

German buttercream, also known as creme mousseline, is a style of buttercream that starts with a thick custard base. Whole eggs are cooked with cornstarch and milk to create a rich custard. This custard is then cooled and beaten into butter. 

German buttercream is by far my favorite flavor of buttercream. It is slightly rich in flavor and has the perfect texture and level of sweetness. 

How Does German Buttercream Compare to Other Styles of Buttercream? 

German buttercream has a very different flavor compared to the other styles of buttercream. It tastes very much like a custard- almost like ice cream. I feel like this is the perfect buttercream for people who don’t like buttercream!

It is softer and less stable than meringue buttercreams, like swiss meringue buttercream. It pipes very well on cupcakes but won’t do well for very intricate piping work. 

How to Make Creme Mousseline

Step 1: Heat the Milk

Milk heating in a pot on the stove

Add the milk to a saucepan over medium heat. If you wanted to make a flavored buttercream, you could steep things in the milk at this point like a vanilla bean, coffee beans, or fresh mint. 

Step 2: Whisk Eggs with Sugar & Cornstarch

Eggs, sugar and cornstarch whisking in a bowl

While the cream is heating, whisk the eggs with the sugar and cornstarch until well combined. 

Step 3: Temper the Eggs 

Hot milk tempering into the egg mixture

Once the milk comes to a simmer, turn off the heat. Slowly stream about half of the hot milk into the egg mixture while whisking continuously. It helps to place a wet towel under the bowl to help stabilize it while you whisk. 

Step 4: Cook the Custard

Pour the mixture back into the saucepan with the rest of the milk and place it back over medium/low heat. Whisk continuously while the custard cooks and comes to a boil. 

Once the custard starts boiling turn the heat down to low and cook for 2 more minutes while whisking. It will become a little chunky at first and then will smooth out. It will be very thick. 

Step 5: Cool the Custard

Custard base for buttercream, cooling

Spread the custard out in a thin layer to help it cool faster. Place it in the refrigerator for one hour to cool. 

Step 6: Beat the Butter

Beat the butter in the stand mixer all by itself on medium/high speed for about 5 minutes. This will make it very light and fluffy. 

Step 7: Add the Custard to the Butter

Butter being whipped into the custard base

With the mixer running, add one spoonful of custard at a time. Continue mixing until it has all been mixed in. 

Switch to the whisk attachment at the end to whip it and lighten it. 

Tips for Success when Making German Buttercream

  • When you are cooking the custard it is important to whisk continuously! 
  • Be aware that the custard will be extremely thick. It won’t be as thin as a pastry cream. 
Creme Mousseline (German Buttercream)
Yield: About 6 Cups

Creme Mousseline (German Buttercream)

Prep Time 1 hour 15 minutes
Cook Time 10 minutes
Total Time 1 hour 25 minutes

German buttercream, aka creme mousseline, is my all-time favorite style of buttercream. This style of buttercream uses a custard base that is then beaten into butter. This makes it taste like ice cream in my opinion!


  • 1 1/2 cups (355 ml) milk (can be any percent)
  • 1 cup (200 gr) granulated sugar
  • 1/3 cup (38 gr) cornstarch
  • 3 large eggs, room temperature
  • 1 TBSP (15 ml) vanilla extract or vanilla paste
  • 2 1/2 cups (5 sticks, 570 gr) unsalted butter, room temperature


  1. Place the milk in a saucepan over medium heat and bring to a simmer.
  2. Meanwhile, in a medium mixing bowl whisk together the sugar, cornstarch, and eggs until well combined.
  3. Slowly pour about half of the milk into the egg/cornstarch mixture while whisking continuously. It can be helpful to nestle the mixing bowl in a damp kitchen towel to stabilize the bowl so you can whisk with one hand.
  4. Pour the milk/egg mixture back into the pot with the remainder of the milk and cook over medium/low heat, whisking continuously, until the mixture thickens and comes to a boil. Once the mixture is boiling, turn the heat to low, and continue whisking vigorously for 2 minutes. The mixture will look lumpy at first but will smooth out as it cooks. This will be a very thick custard.
  5. Remove the custard from the heat and whisk in the vanilla extract. Pour into a shallow dish and press a piece of plastic wrap right on the surface of it. Chill for 1 hour or up to overnight. If you chill for longer than an hour remove it from the refrigerator enough for it to come up to about 50 F (10 C). The custard will become a solid mass as it cools.
  6. In the bowl of the stand mixer fit with the paddle attachment, beat the butter on medium high speed for about 5 minutes until light and fluffy.
  7. Add the custard to the mixing bowl one spoonful at a time while the mixer is still running. Scrape down the sides of the bowl periodically as needed. Continue mixing until all of the custard has been added.
  8. Switch to the whisk attachment and whip on medium/high speed for about 4 minutes until light and fluffy.
  9. Use the frosting immediately or store covered in the refrigerator for up to 3 days. Re-whip before using.

*This is enough buttercream to frost about 24 cupcakes, or to frost a 2 layer 8" or 9" cake or a 9x13" sheet cake.


*Recipe adapted from the German Buttercream Recipe in The Professional Pastry Chef

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