Preheat your oven to 350°F (175°C) and grease your muffin tin or line it with muffin liners.
In a large mixing bowl, whisk together flour, sugar, baking powder, salt, and 1 tablespoon of cinnamon until well combined.
In a separate bowl, beat the eggs, then add milk, melted butter, and vanilla extract. Mix everything together until smooth.
Pour the wet ingredients into the dry ingredients and stir until just combined. Do not overmix; it’s okay if there are a few lumps.
Divide the batter evenly into the muffin tin, filling each cup about ⅔ full.
Bake in the preheated oven for about 18-20 minutes, or until a toothpick inserted in the center comes out clean.
While the muffins are baking, prepare the cinnamon sugar topping by mixing ½ cup of sugar with 1 tablespoon of cinnamon in a small bowl.
Once the muffins are baked, remove them from the oven and let them cool for about 5 minutes. Brush each muffin with melted butter and roll them in the cinnamon sugar mixture until fully coated.
Allow the muffins to cool on a wire rack before serving.