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