Lightly grease and flour your preferred baking pan: a standard-sized bundt pan, a 9x13 inch pan, or two 8x8 inch rounds.
In a small bowl, mix together the milk and vinegar, then set aside.
In a mixing bowl, combine the dry ingredients on low speed.
Gradually add the wet ingredients to the dry ingredients, except for the food dye. Mix until smooth.
Add the food dye to achieve the desired color (see notes at the bottom of the recipe for tips on achieving a deeper black velvet color).
Once all the ingredients are well combined, pour the batter into the prepared pan.
Bake according to the following times: 25-28 minutes for 8x8 inch pans, 30-35 minutes for a 9x13 inch pan, or 40-45 minutes, or until a toothpick inserted into the center comes out clean.
Remove the cake from the oven and allow it to cool in the pan for 15-20 minutes.
Transfer the cake from the pan to a cooling rack to cool completely.
Once cooled, frost and decorate the cake as desired.