Preheat your waffle iron. In a medium-sized bowl, combine Bisquick mix, brown sugar, and cocoa powder. Whisk until well mixed.
Add buttermilk, whole milk, red gel food coloring, egg, melted butter, and vanilla extract to the dry ingredients. Whisk the waffle batter until it becomes smooth.
Pour about ¾ cup of the red velvet batter into the hot waffle iron.
Close the waffle iron and cook the waffle for about 4-5 minutes. Cooking times may vary, so refer to your waffle iron guide for specific instructions.
Once done, the waffles should easily pull away from the iron without sticking. They will have a soft interior, a slightly crispy exterior, and a lightly browned surface.