01 -
Preheat your oven to 375°F (190°C) and line a muffin tin with paper liners.
02 -
In a large bowl, combine the flour, granulated sugar, baking powder, and salt.
03 -
In a separate bowl, whisk together the milk, melted butter, egg, and vanilla extract.
04 -
Pour the wet ingredients into the dry ingredients and stir just until combined.
05 -
In a smaller bowl, mix together the brown sugar and cinnamon.
06 -
Fill each muffin cup halfway with the batter, then sprinkle with the cinnamon-sugar mixture. Add the remaining batter on top, filling each muffin cup about 3/4 full.
07 -
Swirl the remaining cinnamon-sugar mixture into the tops of each muffin with a toothpick or knife.
08 -
Bake for 18-20 minutes or until a toothpick inserted into the center comes out clean.
09 -
Allow the muffins to cool in the pan for 5 minutes before transferring to a wire rack.
10 -
While the muffins cool, prepare the glaze by combining the powdered sugar, milk, and vanilla extract.
11 -
Drizzle the glaze over the cooled muffins and serve.