Preheat your oven to 375°F (190°C). Line a 12-cup muffin tin with paper liners.
In a medium bowl, whisk together flour, sugar, baking powder, salt, and cinnamon.
In a large bowl, whisk together melted butter, milk, eggs, nutmeg, and vanilla extract.
Add the dry ingredients to the wet ingredients and stir until just combined. Do not overmix.
Divide the batter evenly among the muffin cups.
Bake for 20-25 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Allow the muffins to cool in the tin for 5 minutes before transferring them to a wire rack to cool completely.
In a shallow dish, mix together ½ cup granulated sugar and 1 tablespoon ground cinnamon.
While the muffins are still warm, dip the tops into the cinnamon sugar mixture, pressing gently to adhere.
To achieve a crispy top, try baking the muffins for an additional 2-3 minutes. Keep an eye on them to avoid overcooking.
Store cooled muffins in an airtight container at room temperature for up to 3 days. Reheat in the microwave or oven until warm and crispy.
