Preheat the oven to 375°F. Line a standard muffin pan with cupcake papers.
To make the cupcakes: Combine the dry ingredients, then mix in the butter until crumbly.
1 1/2 cups cake flour, 1 cup sugar, 1 1/2 teaspoons baking powder, 6 tablespoons unsalted butter, 1/4 teaspoon salt
Whisk together the eggs, milk, and vanilla. Stir the wet ingredients into the dry in two additions.
2 large eggs, 1/2 cup 2% milk, 1 1/2 teaspoons vanilla extract
Scoop about 1/3 cup batter into each muffin cup.
Bake the cupcakes for 16 to 18 minutes, until they're lightly browned and a toothpick inserted into the center of one of the middle cupcakes comes out clean.
Remove the cupcakes from the oven; after 5 minutes turn them out of the pan onto a rack to cool.
To make the frosting: Beat together the butter, shortening, and salt.
6 tablespoons unsalted butter, 1/3 cup vegetable shortening, 1/4 teaspoon salt
Add the sugar, vanilla, and ¼ cup milk, and beat until fluffy. Add additional milk if the frosting seems too stiff to spread.
4 to 5 cups confectioners' sugar, 2 teaspoons vanilla extract, 1/4 to 1/3 cup milk, Green food coloring
Separate Peeps bunnies from each other. Put a toothpick in the bottom of each bunny and stick into top of frosted cupcake.
Notes
Remember to tell people the bunnies are secured with toothpicks.