Preheat your waffle iron according to the manufacturer's instructions until it is hot and ready to cook.

In a large bowl, whisk together the 2 cups all-purpose flour, 2 tablespoons sugar, 4 teaspoons baking powder, and 1/2 teaspoon salt until evenly combined.

Warm the 1 1/2 cups milk until slightly warm (about 1 minute in the microwave or gently on the stovetop). Do not heat so hot that it cooks the eggs.

In a separate small bowl, whisk the 2 eggs until blended.

Stir the warm milk, 6 tablespoons melted butter, and 1 teaspoon vanilla extract into the whisked eggs until combined.

Pour the wet ingredients into the bowl with the dry ingredients and whisk gently until just blended; a few small lumps are fine—do not overmix.

If your waffle iron is not nonstick, lightly brush or spray it according to the manufacturer's recommendations.

Scoop batter onto the preheated waffle iron (amount per waffle depends on your iron) and cook until the waffles are golden brown and crisp and the steam has mostly stopped, following your waffle iron's cook-time guidance.

Transfer cooked waffles to a cooling rack to keep them crisp and serve immediately, or cool completely and store in zip-close bags in the freezer.