How to Make Flour Buttercream (Yep, Flour!)

Maybe you love how easy it is to make American buttercream , but aren't crushing on its taste and texture. Or maybe you're wild about the taste and texture of Swiss meringue buttercream but think, why does it have to be such a hassle to prepare?!

We’ve got the ultimate frosting for you: flour buttercream.

Sometimes known as ermine frosting or cooked-milk buttercream, flour buttercream combines the ease of American buttercream with the lightly creamy texture and not-too-sweet taste of Swiss meringue buttercream. As a bonus, it holds up extremely well in warmer temps. What more could you ask for?

A better name, perhaps! Because "flour buttercream" sounds like you're gonna get a mouthful of flour — yuck! I prefer to call it “pudding buttercream” or “cooked-custard frosting.” Whatever: It's delicious.

A few quick notes about this recipe. I’m using cornstarch rather than flour as a thickener because it lets you quickly cook the custard base in the microwave. If you prefer to use flour, double the amount and cook the custard in a pot on the stove. The recipe can also be made dairy-free by swapping in any non-dairy liquid for the milk and shortening for the butter. 

Flour Buttercream 

Makes 2 cups


  • 1 cup milk
  • 1 cup sugar
  • 2½ tablespoons cornstarch
  • Pinch salt
  • 2 teaspoons pure vanilla extract
  • 1 cup (2 sticks) unsalted butter, room temperature

Let's Bake!

1. Mix

Place milk, sugar, cornstarch and salt in a microwave-safe bowl and whisk until combined. (To save on cleanup, I use the 4-cup Pyrex cup I used to measure the milk.)

2. Microwave

Microwave the milk mixture for 2 minutes on high. (Put it on a plate in case the mixture bubbles over a bit). The sugar will settle on the bottom, so stir the mixture well with a rubber spatula.

Microwave the milk mixture for another 2 minutes on high.

3. Thicken it Up

Stir again and cook for another 2 to 3 minutes on high. At this point the mixture will have thickened significantly. It should be about the consistency of mayonnaise and able to hold a clear line when you run your finger across the spatula.

4. Add Vanilla

Whisk in the vanilla extract until it's well combined.

5. Cover and Cool

Pour the custard into a shallow bowl or plate. Press plastic wrap against the surface of the custard to keep it from forming a skin. Allow it to cool completely by letting it sit at room temperature or putting it in the refrigerator.

6. Thaw the Butter

If you haven’t done so already, take the butter out of the refrigerator so it comes to room temperature while the custard is cooling.

7. Cream the Butter

Place the softened butter in the bowl of a stand mixer fitted with the paddle attachment (or use a hand mixer) and cream it until light and fluffy, about 3 to 5 minutes.

8. Add the Custard

Scrape down the sides of the stand-mixer bowl. Then, while the mixer is running on low, add the cooled custard to the creamed butter a little at a time until fully incorporated.

9. Beat Until Fluffy

Turn the mixer speed up to medium and beat until light and fluffy, about 3 to 5 minutes more. You're done!

Use your flour buttercream right away or store it in an airtight container in the refrigerator for up to 5 days.

Enjoy your best-of-both-worlds frosting!

Photos via ErinBakes

February 15, 2019
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How to Make Flour Buttercream (Yep, Flour!)