Root beer float cupcakes

Name: Root beer float cupcakes
Ingredients: 2 and 1/2 cups all-purpose flour; 2 and 1/2 teaspoons baking powder; 1/2 teaspoons salt; 3/4 cup (1 and 1/2 sticks) unsalted butter, softened; 1 and 1/2 cups granulated sugar; 3 eggs; 1 Tablespoon root beer extract or 1 teaspoon root beer concentrate; 1/2 teaspoon vanilla extract; 1 cup root beer; 1 cup (2 sticks) unsalted butter, softened; 3 cups powdered sugar; 3 Tablespoons root beer; 1 teaspoon root beer extract or 1/4 teaspoon root beer concentrate; 1 teaspoon vanilla extract