In a large mixing bowl, whisk the eggs, sugar, and salt until smooth and well combined.
Add the milk, melted butter, and vanilla extract. Whisk until combined.
Add the flour and baking powder. Stir gently just until no dry streaks remain. Do not overmix.
The batter should be thick but pourable. If it is too thick, add 1–2 tablespoons of milk. If it appears too thin, add flour 1 tablespoon at a time.
Let the batter rest at room temperature for 5–10 minutes.
Preheat the waffle iron according to the manufacturer’s instructions. Lightly grease it if necessary.
Pour the appropriate amount of batter into the hot waffle iron. Close the lid and cook until the waffle is golden brown and releases easily.
Transfer the cooked waffle to a wire rack. Repeat with the remaining batter.
Serve warm with maple syrup, fresh fruit, powdered sugar, yogurt, or your favorite toppings.