-
Preheat the oven to 350 degrees.
-
Combine the butter, water, and cocoa powder in a small saucepan set over medium heat. Stir constantly until the butter is completely melted. Remove from the heat and set aside.
-
Stir the flour, sugar, baking soda, and salt together in a large mixing bowl. Pour the chocolate-butter mixture into the dry ingredients and stir until just incorporated (the batter will be thick).
-
Add the eggs, buttermilk, and vanilla and stir until smooth.
-
Set an ice cream cone in each of 10 muffin cups. (Be sure none of the cones have holes in them or the batter will leak out and make a mess.)
-
Fill each ice cream cone with cupcake batter to within about 1 inch from the top.
-
Bake for 32 to 38 minutes, until a toothpick inserted into the center of the cupcakes comes out clean. Cool completely, then make the frosting.