A perfect formula for the best, fluffiest American buttercream. This is a buttercream that isn't too sweet, holds its shape perfectly when piped, and can be adapted to any flavor to complement your cakes.
All recipes on Curly Girl Kitchen are developed for high altitude at 5,280 feet.
1tspmeringue powder(optional, but it adds stability)
Beat butter for 1 minute with whisk attachment.
Combine powdered sugar with meringue powder, salt, and any other dry ingredients you might be using, such as espresso powder, freeze dried fruit powder, etc. With the mixer running on low, add the dry ingredients to the butter by spoonfuls and mix on low to combine. It will be clumpy at this point.
Add vanilla, along with any other wet ingredients you're adding, like jam or fruit reductions or gel food coloring. Wait to add the milk until you need it for desired consistency.
Increase speed to medium high and whip for 4-5 minutes until impossibly light and fluffy, scraping the bowl several times, and adding the milk if needed. Turn the mixer down to low and mix for 1 minute - this helps to eliminate some of the bigger air bubbles throughout the buttercream if you're trying to frost your cake with a smooth finish.
If using any add-ins, such as chopped chocolate or nuts, fold them in with a spatula after whipping the buttercream. Be careful of adding whole pieces of fruit or anything that contains water, as it will dissolve the sugar and turn the buttercream too liquidy.
This makes 1 1/4 cups of buttercream, which is enough to frost 8-10 cupcakes or a single layer of cake.
The recipe needs to be multiplied by 3x or 4x to have enough to frost a 2-3 layer cake or 24 cupcakes, depending on how much you like to use. For elaborate piping all over an 8-inch 3-layer cake, I will always multiply this recipe by 4x to ensure I have enough, and then freeze any leftover buttercream.
Piping vs Spreading
Remember that you'll use more buttercream if you're piping it onto a cake or cupcakes, than if you're spreading it on with an icing spatula.
Ratio of Ingredients
Understand that these ratios are a guideline, and may vary slightly depending on certain factors; for example, one day you may need an extra half cup of powdered sugar, because you added strawberry jam to the buttercream.
Cream cheese, also, is softer than butter, and it takes more powdered sugar to reach the right consistency for cream cheese buttercreams.
But in general, these ratios shouldn’t vary a whole lot. I have found that by sticking to this formula, I’m never disappointed in the result.
Pinch of Salt
I also usually add a pinch of salt as well, which is a nice complement to sweet buttercream, especially if you’re using nuts like in a butter pecan buttercream. About 1/4 teaspoon of coarse Kosher salt for 3x the buttercream formula is plenty.
Whipping the buttercream not only makes it light and fluffy, but also lightens the color of the butter to a paler shade of yellow, but all-butter buttercream will always be an off-white color, never pure white.
If you’d like a really white buttercream, then substitute half the butter with shortening (using half butter and half shortening also makes a very stable buttercream for a cake that’s going to be sitting out in warmer weather).
The milk or cream also serves as a “placeholder” for other things you might like to add, such as concentrated syrups, like a champagne reduction, or fruit reductions, etc. If using these sorts of flavor additions, they take the place of the milk, although a little milk may still be needed. Sometimes I don’t use the milk at all if my kitchen is extremely warm and the butter is very soft – use your judgement.
It’s always better to have too much buttercream than too little, and leftover buttercream freezes really well for other projects.
Also note that American buttercream is a “crusting” buttercream. This means that after frosting your cake, the surface will slightly dry or crust over, while remaining soft underneath (unlike Swiss or Italian meringue buttercreams, which do not crust over).
This happens in about 30 minutes to an hour, and can be sped up by chilling the cake, which is desirable when you’ve frosted your cake with a crumb coat, and need that to dry and chill before adding your final pretty coat of buttercream.
When decorating with things like sugar pearls or sprinkles, you want to add those to your cake before the frosting crusts over. When adding decorative piping (such as all-over rosettes), or “painting” onto your cake with more buttercream, do this after the frosting crusts over.