Day before: For the cherry mixture, heat port over medium temperature till warm, but not boiling. Pour warm port over cherries and soak overnight.
For the cake, preheat the oven to 350?F and place a rack in the center of the oven. Butter two 9-inch round cake pans or one 9 x 13-inch pan. Lightly dust the sides of the pan(s) with flour, tapping out the excess, and line the bottoms with circles of parchment or wax paper.
In a medium saucepan, cook the chile powder in 1 cup of the water over medium heat until simmering. Remove the pan from the heat, stir in the vanilla, and set aside.
Using a mixer with a wire whip attachment for best results, combine the flours, sugar, baking soda, salt, and cocoa, and beat on low speed until well mixed. Add the softened butter to the dry mixture and beat thoroughly on medium-low speed. The mixture should be a uniform, grainy texture. Raise the speed to medium and gradually add the remaining cup of water and buttermilk. Add the eggs one at a time, beating well after each addition.
Slowly add the hot water - chile mixture and continue to beat just until well combined; be sure not to over-beat. Pour the mixture equally into the pans and bake for 35 - 40 minutes, or until a wooden pick inserted in the center of each layer comes out clean.
To cool, set the pan(s) on a wire rack for 15 minutes. Then turn the cake(s) out onto the rack, remove the paper from the bottom, and immediately re-invert so that the risen tops don't flatten. Let sit until completely cool before frosting.
For the frosting: Combine the butter and cocoa in a large saucepan and melt over medium heat. Stir in the buttermilk. Add the confectioners' sugar a little at a time, stirring with a wire whisk between additions. Stir in the vanilla. The frosting will stiffen as it cools.
For 9 x 13-inch cake: Place the cake on a large serving plate. Lightly grease the ends of chopsticks. Poke holes in the cake with chopsticks, approximately one hole every inch. Drain the port off of the cherries, reserving the liquid. Pour 2 oz of the reserved port evenly over the cake. Spread the frosting over the top and sides of the cake, being sure to fill each hole with frosting. Top the cake with the cherries.
For 9-inch cake rounds: If necessary, trim the tops of the cakes so that they are level. Place one of the cake layers on a 9-inch round serving plate. Lightly grease the ends of chopsticks. Poke holes in the cake with chopsticks, approximately one hole every inch. Drain the port off of the cherries, reserving the liquid. Pour 1 oz of the reserved port evenly over the cake. Spread 1 cup of frosting over the cake layer, allowing the frosting to fill the holes. Place the second layer of cake on the frosted base. Poke holes in the second layer, pouring 1 oz of the reserved port over the top. Use the remaining frosting to cover the top and sides of the cake. Finish the top of the cake by holding the spatula at a slight angle and making several strokes to smooth the top. To decorate the cake, pour the drained cherries over the cake.
This cake is best when enjoyed directly after the final preparation.Makes 10 to 12 Source: