• 1 1/2 cups all-purpose flour
• 1 teaspoon baking powder
• 1/2 teaspoon salt
• 8 tablespoons (1 stick) unsalted butter , room temperature
• 1 cup sugar
• 3 large eggs
• 1 1/2 teaspoons pure vanilla extract
• 3/4 cup milk

• 1 1/4 cup sugar
• 5 large egg whites
• 2 cups (4 sticks) unsalted butter , room temperature
• 1 teaspoon vanilla extract

Cupcake:
Heat oven to 350°.  Line cupcake pan with liners; set aside.

In medium bowl, sift together flour, baking powder, and salt. In bowl of electric mixer fitted with paddle attachment, cream butter and sugar until light and fluffy. Add eggs one at a time, scrape down bowl, and beat in vanilla.

Add flour mixture and milk alternatively, beginning and ending with the flour. Divide batter evenly among liners, about three-quarters full each. Bake until golden and tops spring back to touch, about 20 minutes, rotating pan once if needed. Transfer to wire rack; cool completely.

Buttercream Frosting 
Combine sugar and egg whites in mixer bowl. Place over a pot of simmering water; whisk until hot and sugar is completely dissolved, 3 minutes. Transfer bowl to mixer stand. Using the whisk attachment, beat mixture on high until cooled, about 15 minutes.

Using paddle attachment, add butter, 1 tablespoon at a time, until completely incorporated. Stir in vanilla. If not using immediately, refrigerate in airtight container up to a week, or freeze up to a month. Bring to room temperature, and re-beat or stir vigorously before using.

(To make chocolate frosting, substitute 3 ounces semi-sweet chocolate, melted and cooled for the vanilla extract.)

Makes 5 cups of frosting.

Assembling Marshmallow Sheep and Nesting Baby Bluebird Cupcakes