Halloween Cupcakes

Ingredients (19)

• 1 cup sugar
• 2 ounces (1/4 cup) unsalted butter, softened
• 1/4 cup vegetable oil
• 2 ounces dark chocolate
• 2 teaspoons pure vanilla extract
• 2 eggs
• 2 egg yolks
• 1 cup all-purpose flour
• 1/2 cup cocoa powder
• 1 tablespoon cornstarch
• 1/2 teaspoon salt
• 1/2 teaspoon baking soda
• 1/2 cup sour cream
• 1/2 cup milk
• 1/4 cup warm water
• 2 (16-ounce) cans vanilla frosting
• Gel food coloring, for garnish
• Candy eyes, for garnish
• Sprinkles, for optional garnish