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

In a large bowl, whisk together the flour, granulated sugar, brown sugar, baking soda, baking powder, salt, and pumpkin pie spice until well combined.

Whisk the eggs, pumpkin puree, vegetable oil, milk, and vanilla extract in a separate bowl until smooth.

Pour the wet ingredients into the dry ingredients and mix until just combined. Be careful not to overmix; if there are a few lumps, it's okay.

Divide the batter evenly among the muffin cups, filling each about 2/3 full.

In a small bowl, mix the granulated sugar and ground cinnamon.

Sprinkle the cinnamon sugar mixture evenly over the tops of the muffin batter.

Bake in the preheated oven for 18-22 minutes, or until a toothpick inserted into the center of a muffin comes out clean or with a few moist crumbs.

Allow the muffins to cool in the pan for about 5 minutes before transferring them to a wire rack to cool completely.