Silk satin meets caramel in this luxurious buttercream.  This one’s ideal on a rich flavored layer cake — think pumpkin spice, chocolate, banana.

There are a number of different frosting recipes in my repertoire, and this one is a special favorite.   What makes this a Swiss Meringue Buttercream is the technique of heating egg whites with sugar over a water bath until 140 degrees, then whisking until light, fluffy, and cooled to warm room temp before beating in butter. This version swaps brown sugar for the more traditional white sugar, yielding a delicious caramel undertone to the silky buttercream.  It can feel a little unfamiliar to the new baker but once you get the hang of it you’ll adore the sophisticated flavor of this style of buttercream.  The recipe is based on proportions by weight — so you’ll need a kitchen scale for this recipe for best results.  It’s literally as easy as 1 2 3:  1 part egg white, 2 parts sugar, 3 parts butter.  That’s the recipe!  Lots of photos and description below, so read through before embarking on this recipe and you’ll be primed for success.  Enjoy!

Brown Sugar Swiss Meringue Buttercream
(makes enough to fill and frost one layer cake)

4 egg whites (approximately 4 oz)
1 cup (8 oz) light brown sugar
4 sticks (12 oz) unsalted butter, room temp

In heatproof mixing bowl, mix egg whites and brown sugar.  Heat over a simmering water bath until the mixture reaches 140 degrees, being sure to constantly stir to prevent hot spots.  The sugar will have dissolved in to the egg white by this time.

Transfer bowl to the stand mixer and, using whisk attachment, whisk on medium until it is fluffy and cooled to near room temp. It should be a soft marshmallow consistency.

Switch to paddle attachment and add the room temperature butter, 2 TB at a time while beating on medium speed.  After all the butter has been incorporated the buttercream will lose some volume, and will seem a little soft.

And then it starts to look slightly curdled, and then – – magic!  The buttercream smooths out and makes a whapping sound.  Continue to beat on medium until the buttercream is no longer curdled looking, but looks smooth.

Stop beating the buttercream at this point — and use to fill and frost a cake or cupcakes.  Enjoy!