Grease a standard 12-cup muffin tin with nonstick spray.
In a large bowl, whisk together the pumpkin puree, yogurt, melted butter, and egg.
Stir in the oat flour, sugar, spices, baking powder, baking soda, and salt.
Portion into the prepared muffin tin using about a heaping 1 tablespoon per mini cup. Preheat the oven to 375℉, and rest the batter while the oven heats. Bake for about minutes, until a cake tester inserted into the center comes out clean.
Cool the muffins in the pan for about 5 minutes, then turn them out onto a rack to cool completely.
Notes
Swap all-purpose gluten-free flour - If you wish, you can use 2 ¼ cups of your favorite 1:1 gluten-free flour blend or my homemade gluten free flour blend for the oat flour (although they won't be oat flour muffins!).
For the oat flour - If you can't do oat flour, substitute sorghum flour.
To make dairy-free - Use dairy-free yogurt and non-dairy butter or melted coconut oil for the unsalted butter.
To make refined sugar-free - Swap in ½ cup of pure maple syrup for the brown sugar.
Butternut squash or sweet potatoes - Use a can of butternut squash puree (or make it yourself) in these muffins for a slightly different flavor! You can also make these into sweet potato muffins by using 1 cup of mashed sweet potatoes for the pumpkin puree.