Unsalted butter, room temperature for molds
1/4 cup unsweetened cocoa powder, plus more for molds
1/2 cup all-purpose flour
1/2 cup sugar
1/4 teaspoon baking soda
1/4 teaspoon baking powder
1/4 teaspoon salt
1 large egg yolk
1/4 cup warm water (110 degrees F)
1/4 cup buttermilk
2 tablespoons vegetable oil
1/2 teaspoon pure vanilla extract
Black Swiss Meringue
1/4 cup black sprinkles
Black Italian Meringue Buttercream
Preheat oven to 350 degrees. Butter six 1 1/2-by-3-inch dome flexible baking molds, and dust with cocoa, tapping out any excess. Set aside on a baking sheet.
In the bowl of an electric mixer, sift together cocoa, flour, sugar, baking soda, baking powder, and salt.
Add egg yolk, the warm water, the buttermilk, oil, and vanilla to the flour mixture. Using the paddle attachment, mix on low speed until smooth, about 2 minutes, scraping the sides and bottom as necessary.
Pour batter to within 1/4 inch from the top of each mold. Bake, rotating once, until a wooden skewer inserted in center comes out clean, about 25 minutes.
Invert and unmold cakes onto a wire rack; set aside until completely cool, about 30 minutes. Trim cakes flush with the top of the molds, using a serrated knife.
To create the heads and legs: Fill a medium pastry bag fitted with a coupler with black meringue. Using a #7 pastry tip for the heads and a #4 pastry tip for the legs, pipe directly onto a parchment-lined baking sheet, keeping the pastry bag at a 45-degree angle to the baking sheet. After piping the heads, carefully affix sprinkles for eyes and mouths. Transfer to oven, bake at 350 degrees.for 5 minutes; set aside.
Using an offset spatula, spread black buttercream over each cake to evenly coat. Cover with black sprinkles; set aside.
Transfer the remaining buttercream to a small disposable pastry bag; snip off the end to make a small hole for piping. Carefully pipe a small amount of icing onto the end of one of the spider legs, and attach to one of the spider-body cakes; apply a small amount of pressure to insert the leg into the frosted body. Repeat with remaining legs and cakes.
Pipe a small amount of buttercream onto the front of one of the bodies, and carefully attach the head. Allow to set; carefully transfer to serving plate by sliding a large spatula under the body from the back of the cake. Repeat with remaining cakes and heads.
Pairs Well With
To make these sinister-looking cakes, you'll need six 1 1/2-by-3-inch dome silicone baking molds, a medium pastry bag with coupler, and a #7 and #4 pastry tip.
Makes 6 cakes.