Preheat your waffle iron to medium-high heat according to its manufacturer's instructions.

In a large bowl, whisk together the eggs, milk, melted butter, and vanilla extract until they are well combined.

Add the buckwheat flour, sugar, baking powder, baking soda, and salt to the wet ingredients. Stir until just combined; it’s okay if there are small lumps, just don’t overmix. Let the batter rest for 5 minutes to thicken slightly.

Lightly grease the preheated waffle iron with cooking spray or butter. Pour about  cup of batter per waffle onto the iron (the amount will vary depending on your waffle maker size).

Close the lid and cook for 4–5 minutes, or until steam stops escaping and the waffles are golden brown and crisp. Carefully remove and repeat with the remaining batter.

Serve the waffles warm immediately with your favorite toppings like maple syrup, fresh fruit, butter, or whipped cream.