rainbow cake with german buttercream recipe -- sky-girl's fifth birthday!
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Recipe type: Dessert
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This recipe is actually just for the buttercream. For the rainbow topper, follow the instructions and photos in the post. The tutorial I followed was from http://cakesdecor.com/entries/229. Choose whatever cake recipe you prefer. Lemon or vanilla are great. I used two 8-inch rounds and one 7-inch round. I had plenty to fill and cover the cake and about 2-3 cups leftover.
Ingredients
  • 16 ounces whole milk
  • 1 teaspoon vanilla extract
  • 1 teaspoon lemon extract
  • 1½ cups sugar
  • ⅓ cup cornstarch
  • 2 eggs
  • 2 egg yolks
  • 16 ounces unsalted butter, softened
  • 16 ounces mascarpone cheese, room temperature
  • ½ teaspoon salt
  • juice of one small lemon
Instructions
  1. Simmer milk in a sauce pan.
  2. Whisk the cornstarch, sugar, yolks, and eggs in a mixing bowl. Once the milk simmers, whisk a ladle of the hot milk into the eggs. Do one ladle at a time, whisking constantly, to temper the eggs. You do NOT want scrambled eggs. After about half the milk is added, then pour the entire mix back into the pot and continue to cook. Cook this mixture stirring constantly at a simmer until thick and bubbles slowly like hot lava. Cook for a full minute to fully cook the cornstarch.
  3. Remove from heat and transfer to a large mixing bowl. Cool in fridge with plastic wrap on top to prevent skin from forming OR cool while mixing at medium speed in a stand mixer. The pastry cream must be completely cooled before proceeding to next step. If it is warm at all, the butter and mascarpone will melt when you add them. If you chill in the fridge and the mixture is cold, then beat for a few minutes on medium until creamy before proceeding.
  4. Now, add the very soft butter one tablespoon at a time. Then do the same with the mascarpone.
  5. Add the lemon juice and salt and whip until smooth and creamy.
  6. Use the buttercream right away, or refrigerate or freeze. Bring to room temperature and whip until fluffy before using.
  7. If the buttercream breaks (curdly mess!), look at my buttercream post on how to fix it.
  8. Frost the cake with crumb coat, chill, then add thicker coat. I frosted the night before and chilled (this is not a buttercream you can leave at room temperature for a day or two).
  9. ADD THE RAINBOW: I chilled the cake a little before I added the rainbow to make sure it could withstand the weight. Before putting it into the cake, measure the height of the cake and the length of the lollipop sticks. Trim if needed.
Recipe by story of a kitchen at https://www.storyofakitchen.com/dessert-recipes/rainbow-cake-with-german-buttercream-recipe-sky-girls-fifth-birthday/