This recipe makes more than enough for 2 8" or 9" layers, with a good amount for between the layers. This is the cake that my granddaughter wanted for her 15th birthday.
Best WHITE WHIPPED BUTTERCREAM FROSTING
1/2 cup unsalted butter, room temperature
1/2 cup shortening (Crisco)
4 cups powdered sugar
1 teaspoon vanilla extract (if you can find PURE clear vanilla that's best ~ but I can only find it in Mexico or at customs before we leave)
1/4 teaspoon salt
1/4 cup heavy whipping cream
In a large bowl or stand mixer fitted with paddle attachment, cream together softened butter and shortening until fluffy and well combined.
Add the powdered sugar, vanilla extract, and salt. Mix until well blended. The frosting will be very stiff at this point.
Slowly mix in the heavy cream on low speed. Once it is fully mixed in, increase the speed to high and beat for 5-7 minutes, scraping down bowl occasionally.
The frosting is very white and fluffy, like a bowl of sturdy whipped cream. Store frosted cake at room temperature for several days. (PERFECT consistency for kids to run their fingers through! With 5 teenagers there, and my daughter who also runs her fingers through frosting, sometimes there's barely any frosting left by the time the cake is cut!)
Enough for a 2-layer cake or 24 cupcakes. It's at least 1/2" thick on the sides of the cake and at least 1" thick on top, plus about 3/4" to 1" filling inside, so LOTS of filling in this recipe.