01 - Whisk together flour, sugar, baking powder, baking soda, and salt in a large bowl until thoroughly combined.
02 - In a separate bowl, whisk together buttermilk, eggs, melted butter, and vanilla extract until smooth and well blended.
03 - Gently fold the wet mixture into the dry ingredients, mixing just until combined. Take care not to overmix to maintain tender texture.
04 - Divide batter evenly between two bowls. Add cocoa powder and red food coloring to one bowl; stir until thoroughly blended to achieve deep red velvet color. Leave second bowl as plain vanilla batter.
05 - Preheat waffle iron according to manufacturer instructions. Lightly grease cooking surface with oil or nonstick cooking spray.
06 - Spoon alternating dollops of red velvet and vanilla batters onto center of hot waffle iron. Use chopstick or butter knife to gently swirl batters together, creating marbled effect without fully blending colors.
07 - Close lid and cook until waffles are golden brown, crisp, and cooked through, approximately 3–5 minutes per batch depending on iron temperature.
08 - Serve immediately while warm. Accompany with cream cheese glaze, maple syrup, fresh berries, or whipped cream as desired.