Preheat oven to 325 degrees F.
Grease and flour a 10-inch bundt pan or tube pan.
Cream the butter and shortening until smooth.
Gradually add sugar, beating until light and fluffy.
Add the eggs, one at a time beating until just incorporated after each addition.
Stir together the flour, baking powder, and salt.
Add flour alternately with the milk beginning and ending with the flour.
Stir in vanilla.
Transfer half the mixture to another bowl.
To one batch of batter, add cocoa and food coloring. Stir until combined.
Evenly pour half of the vanilla pound cake batter into the prepared pan.
Top that layer with half of the red velvet pound cake batter. Spread evenly.
Repeat with remaining vanilla then red velvet batter. Smooth the top.
Bake at 325 degrees F for 1 hour to 1 hour 10 minutes. The cake will be done when a wooden pick inserted in the thickest part comes out clean or with dry crumbs.
Cool on a wire rack for 20 minutes before inverting the cake on serving tray.
Cool cake completely.Bring
When cooled, frost with Buttermilk Glaze.