Preheat your oven to 375°F (190°C). Line a 12-cup muffin tin with paper liners or lightly grease the cups.
In a large bowl, whisk together the flour, granulated sugar, brown sugar, baking powder, baking soda, salt, cinnamon, nutmeg, and ginger until well combined.
In a separate bowl, whisk the pumpkin puree, eggs, oil, milk, and vanilla until smooth.
Pour the wet ingredients into the dry ingredients.
Stir gently with a spatula just until no dry streaks remain. Do not overmix—a few small lumps are fine.
Fold in any optional mix-ins. Divide the batter evenly among the muffin cups, filling each about 3/4 full. Sprinkle tops with coarse sugar if using.
Bake for 18–22 minutes, or until the tops are set and a toothpick inserted in the center comes out clean or with a few moist crumbs.
Let muffins cool in the pan for 5 minutes, then transfer to a wire rack to finish cooling.
Enjoy warm or at room temperature.