These turned out pretty well (unlike the pumpkin blondies I made, which were bad enough to get tossed. Those will not be on the site).
1 1/2 cups all-purpose flour (have successfully swapped whole wheat flour for half)
1 teaspoon baking powder
1/2 teaspoon baking soda
1/2 teaspoon table salt
1 teaspoon pumpkin-pie spice (or 1/2 teaspoon cinnamon + 1/4 teaspoon fresh nutmeg + 1/4 teaspoon ginger + pinch of ground cloves and allspice)
1 cup (original recipe) to 1 1/3 cup (what I use these days; makes it even more rich) canned solid-pack pumpkin (from a 15 ounce can, not pumpkin pie filling, which is sweetened and spiced)
1/3 cup vegetable or another neutral cooking oil
2 large eggs
1 1/4 cups plus 1 tablespoon granulated sugar
1 teaspoon cinnamon
Heat oven to 350 degrees. Put liners in 12 standard-sized muffin cups.
Stir or whisk together flour, baking powder, baking soda, salt and spice in small/medium bowl.
In a larger bowl, whisk together pumpkin, oil, eggs and 1 1/4 cups sugar. Add dry ingredients to wet and stir until just combined. Divide batter among muffin cups (each about 3/4 full).
Stir together last tablespoon of sugar and teaspoon of cinnamon. Sprinkle over each muffin.
Bake until puffed and golden brown and wooden pick or skewer inserted into the center of a muffin comes out clean, 25 to 30 minutes.
Cool in pan on a rack five minutes, then transfer muffins from pan to rack and cool to warm or room temperature.
Do ahead: Most muffins don’t keep well, but these are excellent on Day 2 (after being stored in an airtight container at room temperature) and not bad at all on Day 3. If longer, I’d keep them in the freezer until needed.