Preheat your oven to 375°F and grease a 24-count mini muffin pan thoroughly.

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

In a separate bowl, whisk together the milk, egg, melted butter, and vanilla until smooth.

Gently pour the wet mixture into the dry mixture and stir until just combined (do not overmix).

Spoon the batter into the mini muffin cups, filling each one about 2/3 of the way.

Bake for 10–12 minutes until the tops are domed and the edges are lightly golden.

Let cool in the pan for 2 minutes before transferring to a serving plate.