01 - Whisk together flour, sugar, baking powder, baking soda, and salt in a large bowl until evenly combined.
02 - In a separate bowl, whisk buttermilk, eggs, melted butter, and vanilla extract until smooth and well blended.
03 - Gently fold the wet mixture into the dry ingredients just until combined. Avoid overmixing to keep waffles tender.
04 - Divide batter evenly between two bowls. Add cocoa powder and red food coloring to one bowl; stir until thoroughly blended and evenly colored. Leave the second bowl plain for vanilla batter.
05 - Heat waffle iron according to manufacturer instructions. Lightly grease cooking surface with oil or nonstick spray.
06 - Spoon alternating dollops of red velvet and vanilla batters onto the center of the hot iron. Use a chopstick or butter knife to gently swirl together for a marbled effect.
07 - Close lid and cook until waffles are golden brown, crisp on the outside, and cooked through, approximately 3 to 5 minutes per batch.
08 - Serve immediately while warm. Top with cream cheese glaze, maple syrup, fresh fruit, whipped cream, and berries as desired.