Preheat the oven to 425°F. Prepare a 12-cup muffin tin by lining or greasing every other cup (this will help create taller muffins with better air circulation).

In a medium bowl, mix together the dry ingredients: flour, baking powder, baking soda, cinnamon, pumpkin spice blend, and salt. Set this mixture aside.

In a large bowl, combine the wet ingredients: melted butter, pumpkin puree, brown sugar, egg, and vanilla extract. Whisk until well blended.

Add the dry ingredients to the wet mixture and stir until just combined. Be careful not to overmix. For taller muffins, let the batter sit at room temperature for 15-20 minutes before scooping.

Divide the batter evenly among the 6 muffin cups. Sprinkle each with a generous amount of turbinado or granulated sugar.

Bake at 425°F for 5 minutes. Then, lower the oven temperature to 350°F without opening the door and bake for an additional 12-15 minutes. Muffins are done when they are domed and set, and a toothpick inserted into the center comes out clean or with a few crumbs.

Allow the muffins to cool slightly before enjoying!