Preheat oven to 375°F.
Line muffin tin with paper cups.
Mix flour, sugar, baking powder, salt, cinnamon.
Whisk pumpkin, butter, eggs, milk separately.
Combine wet and dry ingredients gently.
Mix brown sugar, cinnamon, melted butter.
Fill muffin cups halfway with batter.
Add cinnamon mixture on top.
Swirl gently with toothpick.
Bake 18-20 minutes until golden.
Cool 5 minutes before removing.