This recipe is written assuming that you want to make both Shirley Temple and Shirley Temple Black cupcakes. If you want to make an entire batch of original cocktail Shirley Temple cupcakes, just replace the Kahlua with grenadine, and for an entire batch of Shirley Temple Black cupcakes, vice-versa. I like to give my cupcakes a stately crown of frosting but not everybody is into that much on one cupcake. Feel free to half the Grenadine Buttercream recipe.
Line one cupcake pan with 12 paper liners and another cupcake pan with three liners. I used 8 pink liners for the regular Shirley Temple cupcakes and 7 black liners for the Shirley Temple Black cupcakes. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, cream together butter and sugar until light and fluffy. Add eggs one at a time beating well after each addition. Whisk together flour, baking soda, baking powder and salt, set aside. In a medium bowl, whisk together 1/2 cup Sprite soda and 1/2 cup sour cream (mixture will fizz and bubble a little). Add flour and Sprite mixture alternately, beginning and ending with flour.
Fill cupcake papers with 1/4 cup level measures of batter. Bake for 17-22 minutes. Let the cupcakes cool completely. When cupcakes are cool, fill a flavor injecting syringe with roughly 1 teaspoon of grenadine. Place the needle in the center of a cupcake and push the plunger as you gently pull the needle up and out of the cupcake. Repeat with 7 more cupcakes. Wash the syringe and repeat process with Kahlua and remaining cupcakes. Set cupcakes aside while you make the frosting.
Mix together the butter and confectioners’ sugar in a stand mixer fitted with the whisk attachment. Begin mixing on low speed until crumbly and then increase to high and beat for 5 minutes. Reduce mixer speed to low and add the grenadine 1 tablespoon at a time; add more grenadine to taste if desired. Beat frosting again for another 5 minutes until light and fluffy. Scrape down the bowl and mix again on the highest setting for 3 minutes.
If you find the buttercream is too stiff, you may add milk or heavy cream 1 tablespoon at a time until the mixture is piping consistency. Transfer the frosting to a piping bag fitted with a large closed star tip, such as Ateco #856. Pipe frosting onto each cupcake in two large swirles and top each with a maraschino cherry. Sprinkle over the white nonpareils.
Store cupcakes loosely covered in plastic wrap or in a plastic cupcake-keeper.
Shirley Temple cocktail recipe with variationYield: 1 serving6 oz. lemon-lime soda, such as Sprite (can use ginger-ale)1 1/2 tablespoons grenadine Maraschino cherry for garnishPour the lemon-lime soda into a Collins glass filled with ice. Add grenadine. Garnish with a cherry and a fancy straw. Stir drink just before sipping. Shirley Temple Black variation: Add 1 to 2 oz. Kahlua and an additional cherry.