Preheat the Waffle Iron: Preheat your waffle iron according to the manufacturer's instructions.

Prepare Dry Ingredients: In a large bowl, whisk together the gluten-free all-purpose flour, granulated sugar, baking powder, and salt. Make sure all the dry ingredients are well combined.

Mix Wet Ingredients: In another bowl, whisk together the milk, eggs, melted butter (or coconut oil), and vanilla extract until the mixture is well combined.

Combine Wet and Dry Ingredients: Gradually pour the wet ingredients into the bowl with the dry ingredients. Gently stir the mixture until just combined. It's okay if there are a few lumps; overmixing can make the waffles tough.

Let the Batter Rest: Allow the batter to rest for about 5-10 minutes. This helps the gluten-free flour blend absorb the liquid and results in better texture.

Cook the Waffles: Lightly grease the waffle iron with a non-stick spray or a bit of melted butter. Pour the batter onto the preheated waffle iron, using the amount recommended by your waffle iron's instructions.