Preheat the oven to 350°F and line a cupcake pan with four paper liners.

In a mixing bowl, cream the softened butter and sugar until light. Add the egg and vanilla extract, then beat until smooth.

In a separate bowl, whisk together the flour, baking powder, and salt. Add half the dry mixture to the wet ingredients, followed by half the milk. Repeat with the remaining dry mixture and milk, stirring just until combined.

Divide the batter evenly among the four liners. Bake for 18 to 20 minutes, or until a toothpick inserted in the center comes out clean. Cool completely on a wire rack.

Melt the chocolate chips in a microwave-safe bowl in 20-second bursts, stirring between each burst until smooth. Dip the open end of each sugar cone into the melted chocolate and set it on a chocolate sandwich cookie to form the hat shape. Let the chocolate set.

Spread or pipe vanilla buttercream frosting on each cooled cupcake. Place one cookie-and-cone hat in the center of each frosted cupcake.