Light yet decadent, this German Buttercream is the perfect topping to your favorite chocolate cake recipe. Made by combining custard and butter, this frosting is similar in taste and texture to a whipped cream icing. Though it does require some extra work, it will be well worth it in the end! This German Buttercream is also less sweet than traditional frostings, making it a nice alternative to those who enjoy less sugary icing.
In medium heat-proof bowl, whisk sugar and cornstarch together until combined. Add eggs, whisking until fully incorporated.
In medium sauce pan, bring milk to simmer over medium heat. Ladle 1/2 cup hot milk into egg mixture and whisk to combine. Repeat with two more 1/2-cup additions, then pour egg mixture back into pan. Cook over medium heat, whisking constantly, until custard turns thick and lumpy, about 3-4 minutes. When custard begins to bubble, continue to whisk over heat exactly 2 minutes. Remove from heat and add vanilla and salt; stir to combine.
Spread custard into 13 in. x 9 in. baking dish. Let stand uncovered 25 minutes in refrigerator or 45 minutes at room temperature, until custard cools to 68°F.
In medium bowl, beat butter with an electric mixer fitted with paddle attachment at medium speed 5 minutes or until fluffy and light in color.
Stir cooled custard until smooth. Add custard into butter, one tablespoon at a time, mixing thoroughly until each is combined, scraping sides and bottom bowl often.
When pastry cream is fully incorporated, switch to whisk attachment and whip on medium speed 5 minutes or until the buttercream is light and fluffy.