Preheat your oven to 375°F (190°C) and line a muffin tin with paper liners.

In a large mixing bowl, whisk together the flour, sugar, baking powder, and salt.

In another bowl, combine the melted butter, eggs, milk, and vanilla extract.

Pour the wet ingredients into the dry ingredients and mix until just combined. Be careful not to overmix; a few lumps are okay.

Fill each muffin cup about two-thirds full with the batter.

Bake for 18-20 minutes or until a toothpick inserted into the center of a muffin comes out clean.

Allow the muffins to cool for a few minutes in the pan before transferring them to a wire rack to cool completely.