Preheat your oven to 375°F (190°C). Line a 12-cup muffin tin with paper liners.

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

In a large bowl, whisk the melted butter, milk, eggs, ground nutmeg, and vanilla extract until smooth.

Gradually fold the dry ingredients into the wet mixture, stirring gently until just combined. Avoid overmixing.

Divide the batter evenly among the muffin cups, filling each about two-thirds full.

Bake for 20–25 minutes, or until a toothpick inserted in the center comes out clean. Let the muffins cool in the tin for 5 minutes before transferring them to a wire rack.

In a shallow dish, mix the 1/2 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 ensure good coverage.

Return the coated muffins to the oven for 2–3 minutes to crisp the tops. Watch carefully to avoid overbaking.

Serve warm or at room temperature.