Heat oven to 350° F. Grease and flour an 8 1/2 x 4 1/2 x 2 1/2 -inch loaf pan. Cream sugar and butter until creamy. Add egg yolks and mix well. Combine flour and baking powder; add to egg mixture alternately with milk and vanilla, mixing well after each addition. Set aside 1/2 batter. To other half, add cinnamon, allspice, cloves, and cocoa. Mix thoroughly. Spoon batters alternately into cake pan, using a narrow metal spatula or table knife to swirl lightly and marbleize the 2 batters. Bake 40 to 45 minutes. Let cool 10 minutes; remove from pan. Prepare one of the following glazes.
Orange Glaze:
*Thoroughly blend together and drizzle over cooled loaf.