Heat oven to 350°F; lightly butter three 8-inch cake pans and fit each bottom with an 8-inch circle of parchment paper. Lightly butter the parchment paper. Set aside.
Make the batter: Sift the flour, cocoa, baking powder, cinnamon, and nutmeg in a large bowl and set aside.
Beat butter and sugar together in a large bowl with an electric mixer set on medium speed until fluffy.
Add eggs, one at a time, beating well after each addition, until the mixture is smooth and light.
Alternately add the flour mixture and buttermilk mixture, blending well after each addition.
Divide the batter among the pans and bake until a wooden skewer inserted into the middle comes out clean - about 35 minutes. Cool the cakes in the pan for 20 minutes. Remove cakes and cool. (For cupcakes: Heat oven to 375°F; place cupcake liners in standard cupcake tins and fill each with 1/4 cup of batter. Bake for 22 minutes).
When cakes are cool, trim each of the layers. Place one layer on a cake plate and top with one third of the frosting. Repeat with the second and third layers. (To ensure that cake layers do not shift, cut three skewers to 1/4 inch shorter than the full height of the cake and insert them before icing the top layer). Refrigerate until ready to serve.
To prepare frosting: Blend the cream cheese, butter, orange juice, orange zest, and vanilla in a large bowl, using an electric mixer set at medium speed, until smooth. Add the sugar and continue to beat until light and creamy - about 3 more minutes. Add the food coloring and gently stir until the color is uniform. Chill the frosting until ready to ice the cupcakes or cake.