—1/2 cup granulated sugar—3/8 cup plus 1 tablespoon all-purpose flour—1/8 cup plus 1 tablespoon unsweetened cocoa powder (not dutch-processed)
—3/8 teaspoon baking powder
—3/8 teaspoon baking soda
—1/4 teaspoon salt
—1/2 egg, room temperature (whisk the whole egg, then measure out half)
—1/4 cup sour cream, room temperature
—2 tablespoons vegetable oil
—1 1/2 teaspoons vanilla extract
—1/4 cup boiling water
—vanilla ice cream (about 1 1/2 quarts), softened
—whipped cream
—fudge sauce or chocolate sauce
—sprinkles (we used chocolate jimmies)
—maraschino cherries
Instructions
1. Preheat oven to 350ºF. Line two separate 12-cup muffin tins with foil liners. (If you only have one muffin tin, just bake the cupcakes in two batches, rinsing the tin with cool water before baking the second batch.)
2. In a large, heat-safe bowl, whisk together the sugar, flour, cocoa, baking powder, baking soda, and salt. Add the egg, sour cream, vegetable oil, and vanilla, and fold in just until evenly combined. Add the boiling water, and stir in until smooth.
3. Spoon 1 tablespoon of batter into each muffin cup. It will look like a very small amount, but don’t be tempted to add more. Bake cupcakes in the preheated oven for 8-10 minutes (just until a toothpick inserted into the center of one comes out clean), rotating the muffin tins halfway through the baking time. Cool cupcakes for 10 minutes, and then transfer to a wire rack to cool completely. Place in an airtight container, and freeze for 1 hour before adding ice cream and toppings.
4. Spoon ice cream into cupcakes, and level tops with an offset spatula or palette knife. Transfer each cupcake to the freezer immediately after filling. Freeze cupcakes until ice cream is firm.
5. Just before you’re ready to serve, peel off the foil liners, and top cupcakes with whipped cream, fudge or chocolate sauce, sprinkles, and maraschino cherries (as desired). Do not remove cupcakes from freezer if you’re not prepared to serve. Once ice cream has firmed, foil liners may be removed from cupcakes for serving later, but only take one or two cupcakes out of the freezer at once while removing liners.