03 March 2013

Brown-Butter Buttercream Birthday Cake

Downy Yellow Cake with Brown-Butter Swiss Meringue Buttercream
Brown-Butter Swiss Meringue Buttercream

I have come here today to confess to Almighty God and to you my brothers and sisters that I have sinned.  In full knowledge of the importance of birthday cakes, I did willfully try to get away with making a pound cake for a friend's birthday because I didn't want to be bothered with frosting a layer cake. My feet were only set back on the path to righteousness by a stern rebuke from my friend's husband.

(Okay, not a stern rebuke, but "statement of my friend's mild preference" seems sort of anti-climactic, doesn't it?)

And, as it turned out, a different friend of mine had spurred a thread about brown butter over on Facebook and I had filed away the phrase "brown-butter buttercream" for future use. So I decided that if I was going to frost a cake I was going to do it with style.

The first step is to brown the butter, which is a simple matter so long as you're willing to hang around the kitchen stirring occasionally. I recommend hiring a three-year-old to run up and down a step stool and report on the state of the butter every thirty seconds, but you can manage without if necessary. You can do this a day or so ahead, which will give the butter plenty of time to cool.

I also recommend doing this with a stand mixer, but I managed with a hand-held electric mixer and  you can, too. It just requires a bit of patience.

The recipe I started from made a vat of frosting. I only needed half to frost a two-layer, nine-inch cake. The rest is in my freezer, awaiting the next bout of cake. The recipe here is half of what I made, but feel free to double it if you are making a huge cake or you want to have a bag of buttercream in your freezer in case of cake emergency.I'm considering adding some melted chocolate when I defrost and re-whip the remaining frosting.

This is a buttercream, so it is not going to be stable in hot weather. This might the best frosting in the history of cake, but it is the wrong frosting for summer. Try a cooked flour frosting instead.

Brown Butter Swiss Meringue Buttercream
Try not to eat it all before it touches the cake, unless you really want to.

Brown-Butter Buttercream


1 1/2 pounds unsalted butter

6 ounces egg whites (4-5 large egg whites, 3/4 cup)
1 1/2 cups sugar
1 Tablespoon vanilla extract

To brown the butter:
In a medium sauce pan, melt the butter over medium heat. Allow the butter to come to a boil. Reduce heat to maintain a simmer. Foam will form and then subside. Butter solids will become visible as white flakes. When the white flakes begin to turn brown, remove the pan from the heat. And pour through a fine sieve into a bowl. I do not line my sieve with cheesecloth or a coffee filter because I want the small bits milk solids to remain. They fleck the frosting with tiny bits of extra deliciousness. Allow the butter to cool to room temperature, then move to the refrigerator, where it will keep well for at least a week.

Brown Butter
Browned butter, scooped into balls for easy incorporation into the frosting.
That dark brown stuff is the browned milk solids. They're delicious.

On the day you are going to make the frosting, remove the butter from the refrigerator and set aside to soften.

Mix the sugar and egg whites together in a large, heat-proof bowl, then set it over a pan of simmering water. (If you're using a stand mixer, you can just use the mixer's bowl.) Heat, whisking frequently, until the egg whites are 140 F, or hot to the touch.

Remove the bowl of egg whites from the double boiler and set in on the counter on a slightly damp towel to prevent slipping. Using your hand mixer at full-power, beat the eggs into a fluffy meringue until the bowl is cool to the touch. If the meringue is more than room temperature, then the butter will melt and the texture of the frosting will not be as good. If using a stand mixer, beat with the whisk attachment on high speed until the bowl is cool to the touch.  You should have a stiff, glossy meringue.  It would be a perfectly adequate frosting on its own if you were so inclined.

Swiss Meringue Not Yet Buttercream
Congratulations! You've made marshmallow fluff!

Add vanilla extract to the meringue. With the beater on high speed, begin incorporating the butter a couple of tablespoons-full at a time, pausing occasionally to scrape down the sides of the bowl with a flexible spatula.

Frosting can be used immediately, stored in the refrigerator for several days, or frozen for several months. Chilled frosting should be allowed to come to room temperature slowly over several hours, and then re-whipped before being used.


  1. Good glory. You had me at meringue.

    1. This method makes a Swiss Meringue Buttercream and they are marvelous, creamy, smooth, fluffy . . .

  2. Wow. I'm very, very impressed ... meringue and browned butter are two of my kitchen challenges. But oh, the taste. You're so right.

    Why has it never occurred to me that one could brown butter and then re-refrigerate it for use later? Like ... DUH.

    It doesn't matter that you THOUGHT about pound cake. You MADE the frosted cake, and you have some very lucky friends.

    1. We have never baked together. We should do something about that someday.

      This meringue is very forgiving. I have had most kinds of kitchen failures, but Swiss meringue buttercream always seems to work out, eventually, after a lot of mixing, and wishing I had a stand mixer, and then some more mixing.

  3. Love it! I had the idea to brown butter and then re-refrigerate it to make buttercream, but I'm on a tight budget and didn't want to have to throw it out if it didn't work. Thanks for experimenting for the rest of us. Oh, and the idea of mixing it into a SMBC!!! That just takes it to another level! My only remaining question is... How does this hold up outside on a warm day?

    1. I would not use a SMCB outside on a warm day. Have you tried a cooked flour frosting? They hold up a bit better, and you could use brown butter.

  4. This is just regular sugar, not confectioners' sugar, right? It's just possible that I might decide my life is too simple and that I need to make this tomorrow.

  5. It is just regular granulated sugar. It will dissolve when you cook the egg whites.

  6. Just FYI, I made a small amount using 1 egg white, a stick and a half of butter (6oz), and 1/4 + 1/8 cups of sugar. 1/2 teasp vanilla. It worked out perfectly, even though my butter came out a little darker than yours.



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