Confetti Birthday Cake with Chocolate Buttercream - Master recipes

Ingredients

• 1 cup unsalted butter, softened -
• 1/3 cup vegetable oil -
• 1-3/4 cups sugar -
• 3 large eggs, room temperature -
• 3 large egg whites, room temperature -
• 1 tablespoon vanilla extract -
• 3 cups cake flour -
• 2 teaspoons baking powder -
• 1 teaspoon salt -
• 1 cup buttermilk, room temperature -
• 1/4 cup rainbow sprinkles -
• CHOCOLATE BUTTERCREAM: -
• 8 ounces dark chocolate chips -
• 1/4 cup heavy whipping cream -
• 2 cups unsalted butter, softened -
• 5 cups confectioners' sugar, sifted -
• 1 pinch salt -