Place muffin liners inside the muffin cups. I prefer to have all of them one color, but I’m a little neurotic so do as you please. Preheat oven to 350F.

Whisk together flour and baking powder in a small bowl.

(Here’s the deal with pumpkin-pie spice: they sell it at most grocery stores right now. But I’m not a fan of a one-purpose type of spice, so I put in 1/8 of a teaspoon each of cinnamon, nutmeg, cloves, ginger, and allspice. So if you don’t have pumpkin-pie spice, you can just do what I did.)

Whisk together pumpkin puree, oil, eggs, pumpkin-pie spice, 1 1/4 cups sugar, baking soda, and salt in a large bowl until smooth. Then whisk in the flour mixture until just combined.

Stir together cinnamon and remaining 1 tablespoon sugar in another bowl.

Divide batter among muffin cups (each should be about 3/4 full), then sprinkle the tops with the cinnamon-sugar mixture. Bake until puffed and golden brown and a wooden pick or skewer inserted into center of a muffin comes out clean, about 25 to 30 minutes.

Cool in the pan on a rack for 5 minutes, then transfer muffins from the pan to the rack and cool to warm or room temperature.