I've used this recipe many times, for cakes and cupcakes, and have always been rewarded with dark, dense chocolatey goodness:
Heidi's Chocolate Cake
2 cups all-purpose flour
1 1/2 cups sugar
3/4 cup cocoa powder
2 tsps. baking soda
1 tsp. baking powder
1 tsp. salt
1 cup half-and-half cream
1 cup cold coffee
1/2 cup vegetable oil
1 tsp. vanilla
1. Preheat oven to 350F and line two 12-cup muffin pans with paper liners.
2. Mix flour, sugar, cocoa powder, baking soda, baking powder and salt together.
3. Add cream, eggs, coffee, oil and vanilla, and mix thoroughly.
4. Pour batter into liners, filling them 3/4 full
5. Bake cupcakes for 20-25 minutes, or until knife inserted in the center comes out clean.