Preheat oven to 350°F. Butter 24 muffin tins.
For the cake, whisk cocoa and 1/2 cup lukewarm water in a small bowl. Whisk the remaining 1/2 cup water with the buttermilk in another small bowl. Sift flour, baking soda and salt into a medium bowl and add cinnamon, cloves and cayenne. Stir to combine.
Using electric mixer, beat both sugars and butter in a large bowl until pale yellow and fluffy (mixture will appear granular), about 5 minutes. With mixer running, gradually add beaten eggs; beat until smooth and fluffy, about 15 seconds. Add cocoa mixture; beat to blend. Add flour mixture and buttermilk mixture alternating in 3 additions, beating to blend after each addition. Divide batter among the muffin tins. Bake for10 minutes or until a toothpick comes out clean.