Preheat the oven to 350°F and place the oven rack in the lower position. Wrap a piece of foil over a 12 cup muffin tin. Cut a small x in the foil in the center of each cup. Set aside.
In a large bowl, whisk together the egg, vegetable oil, buttermilk, sugars, and vanilla until smooth.
1 large egg, ¼ cup vegetable oil, ¼ cup buttermilk, ½ cup granulated sugar, ½ cup brown sugar, packed, 1 tsp vanilla extract
Add the flour, cocoa powder, salt, and baking soda. Stir in just until combined.
1 ¾ cups sifted all-purpose flour, ½ cup unsweetened cocoa powder, ½ tsp salt, 1 tsp baking soda
Stir in the hot water.
½ cup hot water
Gently press an ice cream cone into a slit in the foil in the muffin tin cup. Repeat with the remaining cones so you have 1 cone in each muffin tin cup.
12 cake ice cream cones
Divide the batter evenly between 12 ice cream cones, filling them almost 2/3 full.
Bake for 20-30 minutes, or until a wooden toothpick inserted into the center of a cupcake comes out clean.
Transfer to a wire rack and allow them to cool completely.
To make the frosting, beat butter with a mixer – hand or stand – on medium for 2-3 minutes.
½ cup butter
Add 1 ½ cups of the powdered sugar 1/2 a cup at a time, and beat until well-combined.
1 ½-2 cups powdered sugar
Add vanilla and a pinch of salt and beat until well-combined.
1 teaspoon vanilla extract, Pinch salt
Add 1 tablespoon of cream, and beat until combined.
1-2 ½ tablespoons heavy whipping cream
If necessary, continue adding powdered sugar 1/4 cup at a time or cream 1 teaspoon at a time until you reach desired consistency.
Add a swirl of frosting on top of each cupcake.
Top with sprinkles before serving.
Sprinkles
Notes
Cones: I don't recommend using sugar cones or waffle cones because of the pointed tip. The flat bottom on the cake cones let them stand up easily.
Vegetable oil: Or any neutral oil. If you'd prefer to use butter, you will need 1/3 cup butter, melted.
Buttermilk: If you don't have buttermilk, you can use this recipe to make your own buttermilk substitute.
Flour: It's important to properly measure the flour. Weighing it is the most accurate means of measurement. If not, you will need to sift the flour to avoid packing it.
Butter: I use salted butter. If you're using unsalted butter, add a pinch or two of salt to the frosting.