I made this frosting for a particularly epic birthday cake for a friend of mine, and it was so good, I had to share the recipe. It's so silky + smooth, with just a hint of saltiness. It's crazy amazing with chocolate cake and it was made for mini cakes of all sorts.
Salted Peanut Butter Buttercream
Makes about 4 cups
108 g / 4 large egg yolks
113 g / 2 large eggs
397 g / 2 cups granulated sugar
181 g / 3/4 cup water
680 g / 5 sticks unsalted butter
300 g / 1 1/4 cup smooth peanut butter
7.5 g / 1 1/2 teaspoons vanilla extract
3 g / 3/4 teaspoon fine sea salt, or more to taste
1. Place the egg yolks and whole eggs in the bowl of an electric mixer fitted with the whip attachment. In a medium pot, combine the sugar and water over medium heat. Bring the mixture to a simmer, stirring constantly to help the sugar dissolve. Once the mixture comes to a boil, stop stirring (if necessary, brush any sugar that’s washed up on the sides with a pastry brush dipped in cool water). Attach a candy thermometer to the side of the pot (or have a digital thermometer ready)!
2. Cook until the syrup reaches 235°F. When the syrup comes to temperature, begin whipping the egg mixture on medium high speed. The goal is to get this mixture pale yellow and thick by the time the sugar reaches 240°F.
3. When the egg mixture is pale and thick and the sugar has come to temp, pour the syrup in a slow, steady stream into the whipping whites. Continue whipping on medium high speed until the egg mixture has reached full volume and the bowl is no longer warm to the touch, 5-6 minutes.
4. When the mixture is cool, begin adding the butter gradually. Add 1-2 tablespoons at a time with the mixer running on medium speed, letting the butter incorporate before you add more. If the meringue is too warm, it will melt the butter! If the butter is too cold, it will stiffen the meringue!
5. Keep adding until all of the butter is incorporated. Add the peanut butter and salt and mix to combine. The frosting can be used immediately!