01 - In a large bowl, whisk together flour, sugar, baking powder, baking soda, and salt until evenly combined.
02 - In a separate bowl, whisk together buttermilk, eggs, melted butter, and vanilla extract until smooth and homogeneous.
03 - Gently fold the wet mixture into the dry ingredients just until incorporated. Take care not to overmix as this may result in tough waffles.
04 - Divide the batter evenly between two bowls. Add cocoa powder and red food coloring to one bowl; stir thoroughly until fully blended and uniform in color. The remaining batter will be the vanilla portion.
05 - Preheat your waffle iron according to the manufacturer's guidelines. Lightly coat the cooking surfaces with oil or nonstick cooking spray.
06 - For each waffle, alternately spoon red velvet and vanilla batters onto the center of the hot waffle iron. Use a chopstick or butter knife to gently swirl the batters together, creating a marbled effect without completely blending them.
07 - Close the lid and cook until waffles are golden brown, crisp on the outside, and completely cooked through, approximately 3 to 5 minutes per batch depending on your waffle iron.
08 - Serve immediately while warm. Top with cream cheese glaze, pure maple syrup, or fresh berries as desired.