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Brown Sugar German Buttercream

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Luscious German buttercream built on a brown sugar custard base is a flavorful silky smooth way to top your favorite treats. Make some today and see for yourself!

close up of fluffy swirl of brown sugar german buttercream on plate

Super silky smooth brown sugar German buttercream is the perfect way to frost a cake or swirl on top of cupcakes. The brown sugar adds so much flavor and warmth and the custard base makes it so creamy. This not too sweet frosting is quickly going to become a favorite.

You know I am a frosting fanatic, so it shouldn’t be a surprise that I was anxious to create a new frosting when I baked up some pumpkin cupcakes. Of course I have plenty of recipes that would have been wonderful, but I needed something new and different.

I immediately knew I wanted something with brown sugar goodness mixed in. I was tempted to do something along the lines of an American buttercream but with some brown sugar mixed in.

brown sugar german buttercream swirls on top of pumpkin cupcakes

(Do you want to know more about the different types of frosting? Check out my Frosting 101 page to help you determine what makes each one unique.)

I was worried that in order to get enough brown sugar into the mix to get the flavor I was after, the texture might be grainy. I am still tempted to work on that a bit, so don’t be surprised if a recipe pops up here one of these days.

In the meantime German buttercream seemed like the perfect way to go. Because you cook the sugar into a custard, you don’t have to worry about a grainy final frosting.

Plus it was a great way to use brown sugar as the exclusive sweetener instead of diluting that molasses goodness with powdered sugar. And to be honest I have been in love with this method ever since I tinkered with my vanilla German buttercream recipe.

The results were every bit as good as I had imagined. The frosting is sweet but not too sweet.

It is warm and inviting and flavorful and silky smooth. It worked perfectly on pumpkin cupcakes but would also be amazing on banana cupcakes or devilishly good chocolate cupcakes.

The process may seem a bit intimidating, but it’s really not hard. Enjoy the journey and bask in the glory of the results!

Step by step instructions with pictures to help you along the way

The first thing you’ll want to do to make German buttercream is make the custard.  You need to do this ahead of time so it can cool.  In fact you can do it a day or two ahead if you want to space out the time and effort you put into it.

brown sugar, corn starch and whisk in glass bowl for german buttercream

First you will want to whisk together the cornstarch with some of the brown sugar in a small glass (or other heatproof) bowl.

eggs whisked into brown sugar and cornstarch mixture for german buttercream

Now whisk in the eggs until well combined.  Put this mixture by the stove so you are ready when you need it. 

The next few steps are hard to get pictures of as I went.  It’s hard to pour, whisk and photograph all at the same time! 

In a small saucepan, mix together the remaining brown sugar and milk.  Heat over medium heat just until it starts to come to a low simmer. Drop the heat to medium-low.

Ladle about 1/3 cup of the hot mixture into the egg mixture while stirring.  The measurement doesn’t have to be perfect, you just want to temper the eggs a bit.

The key to this step is to keep the egg mixture moving while adding the hot liquid to ensure it doesn’t scramble the eggs.

Once the hot milk mixture is mixed into the egg mixture, slowly pour the tempered egg mixture into the saucepan with the remaining milk mixture. Be sure to whisk vigorously while you are adding the egg mixture.

Again the key is to get the eggs incorporated without curdling or scrambling them.  It really isn’t that difficult, just keep the whisk moving as you add them!

lumpy brown sugar custard mixture in saucepan for german buttercream

Cook over medium-low heat, stirring constantly until the mixture thickens.  It will likely get a little bit lumpy and that is perfectly ok. Just keep stirring until you get to the consistency of a tight pudding or almost to paste consistency.

Turn off the heat and beat it until it becomes smooth.  Now add 2 Tablespoons of butter and stir in.  The mixture should be smooth and slightly glossy.

smooth brown sugar custard mixture on whisk over saucepan for german buttercream

Cover with plastic wrap, allowing the plastic wrap to sit on the surface of the custard to prevent it from forming a skin. Then place in the refrigerator to chill. 

It must come to at least room temperature or colder before you proceed to the next step. Take the remaining butter and chilled custard out of the fridge at the same time.  While the butter softens the custard can also come to room temperature. 

They will mix better if they are at the same temperature.  The chilled custard should be even thicker now,  almost a cookie dough consistency.

whipped butter in stand mixer bowl  with plastic wrap covered chilled brown sugar custard mixture nearby ready to be added

Now beat the butter until it is light and fluffy.  Be sure to scrape down the sides of the mixing bowl as you go to avoid any hidden lumps.

Now with the mixer running, add a couple of Tablespoons of custard at a time to the bowl. As each addition incorporates, add a bit more until it is all added.

stand mixer bowl full of brown sugar German buttercream freshly whipped together

Add a bit of vanilla and a pinch of salt, mixing until just combined. Use immediately or refrigerate until ready to use. 

Tips and Tricks

Make sure you have everything out and ready when you start to make the custard.  It will go quickly once you start.

Don’t let the number of steps scare you off.  I tried to make the instructions detailed to help you along, but the process really isn’t that hard.

Make sure you let your custard get thick.  It should want to stay on your whisk for at least a second or two while it is still warm. If you don’t get it thick enough, your frosting isn’t going to hold its shape later. 

If you find your final frosting is a bit loose you have two options. 1: Chill it before you try to pipe with it. 2: Beat in a little powdered sugar to tighten it up. Then make a note to yourself to let the custard get thicker next time!

More Great Frosting Recipes:

If you like the idea of brown sugar in your frosting, try peanut butter brown sugar buttercream. It is an American style frosting, so it is quick and easy to put together.

For another super smooth, rich frosting try making French maple buttercream. It is so smooth and luscious.

If you like the idea of European buttercreams, but don’t want to have to fuss with cooking anything try mock Swiss meringue buttercream. It uses pasteurized egg whites to make it so much simpler than the classic version.

You can scroll through my Frosting 101 to learn about the different types of frosting, or just check out my full collection of frosting recipes for more inspiration.

Love this recipe? Give it a ⭐⭐⭐⭐⭐ review in the recipe card below!

Swirl of brown sugar buttercream made with a custard base in the style of german frosting.

Brown Sugar German Buttercream

Luscious German buttercream built on a brown sugar custard base is a flavorful silky smooth way to top your favorite treats. Make some today and see for yourself!
5 from 3 ratings
Prep Time 15 minutes
Cook Time 10 minutes
Additional Time 1 hour
Total Time 1 hour 25 minutes
Course Dessert
Cuisine American
Servings 18 Servings
Calories 155 kcal



  • ¾ cup brown sugar divided
  • ¼ cup cornstarch
  • 2 large eggs
  • 1 cup whole milk
  • 2 Tablespoons butter


  • 1 cup butter softened
  • 2 teaspoons vanilla
  • pinch of salt


  • In a small heatproof bowl, whisk together ¼ cup brown sugar and the cornstarch.
  • Add the eggs and whisk to incorporate. Set egg mixture by stove.
  • In a small saucepan, stir together remaining ½ cup of brown sugar and milk.  Heat over medium heat until it starts to steam and come to a low simmer, stirring frequently. Drop heat to medium-low.
  • Ladle about ⅓ cup of hot milk mixture into the egg mixture, whisking as you add the hot milk mixture.
  • Slowly pour the tempered egg mixture into the saucepan with the remaining milk, whisking vigorously as you drizzle the egg mixture in.
  • Cook over medium low heat until it thickens to a tight pudding consistency, stirring constantly.  (Don’t panic if small lumps form as you go.)
  • Turn off heat and whisk vigorously until the mixture is smooth. Add 2 Tablespoons of butter and stir until incorporated.
  • Cover with plastic wrap, placing the plastic wrap on the surface of the custard. Chill for at least an hour but up to a couple of days before proceeding. 
  • Place the remaining butter and chilled custard on the counter at the same time to come to room temperature.
  • Once the butter is softened, beat until light and fluffy. With mixer running, add the custard a couple of Tablespoons at a time until it is all incorporated. 
  • Add vanilla and salt and beat until light and fluffy.
  • Use immediately or chill until ready to use. 


Serving: 1ServingCalories: 155kcalCarbohydrates: 10gProtein: 1gFat: 12gSaturated Fat: 8gPolyunsaturated Fat: 4gCholesterol: 53mgSodium: 115mgSugar: 8g
Tried this recipe?Mention @carleecooks or tag #cookingwcarlee!
Luscious German buttercream built on a brown sugar custard base is a flavorful silky smooth way to top your favorite treats. Make some today and see for yourself!

Thanks for sharing!

Recipe Rating


Thursday 3rd of October 2019

Oh my, this looks and sounds delightful! Who can resist a buttercream!?!


Thursday 26th of September 2019

That sounds delicious! I am wondering about adding a bit of molasses to regular buttercream to achieve the brown sugar flavor since brown sugar is sugar and molasses. I may give it a try.

Jean |

Thursday 26th of September 2019

Carlee, this sounds wonderful! I limit my sugar intake and so just scrape off American buttercream. Love the flavor of brown sugar and butter, a classic combination! #FullPlateThursday