Preheat your waffle iron to medium-high heat for at least 5 minutes while you prepare the batter.
In a large mixing bowl, whisk together the flour, 2 tablespoons sugar, baking powder, salt, and 1 teaspoon cinnamon until evenly combined.
In a separate bowl, whisk the eggs until lightly beaten, then add the milk, 1/2 cup melted butter, and vanilla extract. Whisk until smooth and well combined.
Pour the wet ingredients into the dry ingredients and stir gently with a wooden spoon or spatula until just combined. Small lumps are fine — do not overmix or the waffles will be tough.
In a shallow dish, mix together the 1 cup sugar and 2 tablespoons cinnamon for the coating. Set aside with the 1/2 cup melted butter and a pastry brush.
Lightly grease the waffle iron if needed, then pour the recommended amount of batter for your iron size (typically 1/2 to 3/4 cup). Close the lid and cook until the waffle is golden brown and steam stops escaping, about 4-5 minutes.
Immediately after removing each waffle from the iron, brush both sides generously with melted butter while still hot.
Working quickly, press the buttered waffle into the cinnamon sugar mixture, coating both sides thoroughly. Gently press to ensure the sugar adheres to all the ridges.
Serve immediately while warm and crispy, or keep finished waffles in a 200°F oven on a wire rack until ready to serve. Repeat with remaining batter.
