Melt butter either on the stove or in the microwave. Set aside.

In a large bowl, whisk together flour, sugar, baking powder, salt, and baking soda. In a separate bowl, whisk together yogurt, milk, melted butter, vanilla extract and eggs. Fold wet ingredients into dry ingredients.

Preheat a waffle iron and, using a pastry brush or paper towel, lightly grease the waffle iron. Cook waffles until golden and crisp. Grease the iron in between batches as needed.

Serve waffles immediately as they are ready, or keep them warm in a 200 degree Fahrenheit oven until ready to serve.