Preheat your oven to 375°F (190°C) and grease a mini muffin pan.

In a large mixing bowl, combine flour, sugar, baking powder, and salt. Whisk to combine.

In another bowl, whisk together milk, egg, melted butter, and vanilla extract until smooth.

Pour the wet ingredients into the dry ingredients and stir until just combined; the batter should be slightly lumpy.

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

Bake for 10–12 minutes or until golden brown. Check with a toothpick for doneness.

Cool for 5 minutes, then remove from pan and serve warm.