Preheat your oven to 350°F (175°C) and line a muffin tin with paper liners or grease it lightly.

In a bowl, whisk together the flour, baking powder, baking soda, salt, and cinnamon until well combined.

In another mixing bowl, cream the softened butter and granulated sugar together until light and fluffy, about 2-3 minutes.

Add the eggs one at a time, mixing well after each addition, then stir in the vanilla extract.

Gradually add the dry ingredients to the wet mixture, alternating with the milk. Start and end with the flour mixture, mixing until just combined (do not overmix!).

Divide the batter into the prepared muffin liners, filling each about 2/3 full.

In a small bowl, combine the granulated sugar and cinnamon for the topping. Sprinkle this mixture generously over each muffin.

Bake in the preheated oven for about 18-20 minutes, or until a toothpick inserted into the center comes out clean.

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