Preheat oven to 300 degrees. Line a 9x5 inch loaf pan with aluminum foil and grease the inside.
In a medium bowl whisk together flour, cocoa powder, baking powder, and salt.
In a large bowl or stand mixer, cream together butter and sugar until light and fluffy.
Slowly add the beaten eggs, a little at a time, with your mixer on low speed. If the mixture starts to curdle, add a spoonful of the flour mixture, keep on adding the eggs, and a bit of flour if necessary, until all the eggs are added. Add the vanilla and food coloring.
Add half the milk with half of the flour, keeping the mixer on slow speed. Once combined, add the remaining milk and gently fold in the remaining flour until combined.
Pour mixture into your prepared loaf pan. Bake 55-65 minutes until an inserted toothpick in the center comes out clean (a few crumbs are okay, but no wet batter). Allow to cool on a wire rack.
Prepare the frosting. In a medium bowl cream together butter, cream cheese, powdered sugar, vanilla, and milk until smooth and spreadable. Spread on cooled cake. Slice and serve.
Makes one loaf, with about 8-10 slices depending on the thickness of your slices.