In a large mixing bowl, whisk together all-purpose flour, sugar, baking powder, baking soda, and salt until well combined. In another bowl, whisk buttermilk, eggs, melted butter, and vanilla extract until smooth. Combine wet and dry ingredients gently.

In another bowl, mix together all-purpose flour, sugar, baking powder, baking soda, salt, and cocoa powder. In a separate bowl, combine buttermilk, egg, melted butter, vanilla extract, and red food coloring until well blended. Combine wet and dry ingredients until just combined.

Preheat your waffle iron according to the manufacturer's instructions, usually about 5 minutes. Test readiness by sprinkling a few drops of water onto the iron.

Once your waffle iron is ready, lightly grease it. Carefully pour alternating ladles of the classic and red velvet batters onto the hot surface, creating a swirling effect. Use a toothpick or knife to swirl the batters together gently.

Close the waffle iron and cook according to your appliance's guidelines, about 5-6 minutes, or until waffles are golden brown and crisp.

Once cooked, remove the waffles from the iron and serve immediately with your choice of toppings like whipped cream, fresh berries, or maple syrup.