Heat the oven to 375°F. Line all 12 muffin cups and place the pan in the center of the oven when ready.
Whisk flour, cinnamon, baking powder, baking soda, ginger, nutmeg and salt until evenly dispersed.
In a second bowl, whisk pumpkin, eggs, brown sugar, oil, milk and vanilla until smooth.
Add the dry mixture to the wet. Fold just until no dry flour pockets remain; the batter will be thick.
Divide evenly among 12 cups, about three-quarters full. Add optional pepitas or pecans.
Bake 18 to 22 minutes, until tops spring back and a tester has moist crumbs but no wet batter. Cool 5 minutes in the pan, then move to a rack.
