Ingredients

2 1/2 cups all-purpose flour
3 tablespoons unsweetened cocoa powder (not Dutch-processed)
1 teaspoon baking soda
1/2 teaspoon salt
1 cup buttermilk or 2/3 cup plain low-fat yogurt mixed with 1/3 cup milk
1 tablespoon cider or red wine vinegar
1 teaspoon vanilla extract
1 teaspoon red food-coloring paste or 2 tablespoons liquid red food coloring
8 tablespoons (1 stick) unsalted butter, at room temperature, cut into pieces
1 1/2 cups sugar
2 large eggs, at room temperature

Frosting:
2/3 cup heavy cream
5 ounces bittersweet or semisweet chocolate, finely chopped
Assorted gummy worms and bugs, for decorating the cupcakes

Directions

To make the cupcakes, position a rack in the center of the oven and preheat to 350 F. Line 16 muffin tins (you will use 2 muffin pans with 12 indentations each) with paper cupcake liners, staggering the liners in the tins so they are somewhat evenly distributed. (In other words, don't put all the liners on one side of the muffin pan or the cupcakes could bake unevenly.)

Sift the flour, cocoa, baking soda and salt together. Mix the buttermilk, vinegar, vanilla and food coloring in a glass measuring cup.

Beat the butter in a medium bowl with an electric mixer on high speed until creamy, about 1 minute. Gradually add the sugar and beat until the mixture is very light in color with a sandy texture, about 3 minutes. One at a time, beat in the eggs. On low speed, in three additions, beat in the flour, alternating with two additions of the buttermilk, beating well after each addition and scraping down the bowl as needed with a rubber spatula. Fill each muffin tin about three-fourths full with the batter.

Bake until the cupcakes spring back when lightly pressed in the centers, 18 to 20 minutes. Cool for 5 minutes. Remove the cupcakes from the tins, transfer to wire cake racks, and cool completely.

To make the frosting, bring the heavy cream to a simmer in a medium saucepan over high heat. Remove from the heat and add the chocolate. Let stand for 3 minutes to melt the chocolate, then whisk until smooth. Transfer to a medium bowl. Cool until the chocolate mixture is as thick as chocolate pudding.

Using a wire whisk or an electric mixer on medium speed, whip the chocolate mixture just until it is light and fluffy. Do not overbeat or the frosting will be grainy. Spread the icing over the cupcakes and top with the candies. (The cupcakes can be prepared 1 day ahead and stored in an airtight container at room temperature.)