Preheat the oven to 425℉. Line the muffin cavities with every other order, leaving an empty cavity beside the lined one.
Sift all-purpose flour, baking powder, soda, spices, and salt.
1¾ cups All-purpose Flour, 1 teaspoon Baking soda, 2 teaspoon Baking powder, ¼ teaspoon Salt, 1 teaspoon Cinnamon, 1 teaspoon Pumpkin Spice
Whisk pumpkin puree, eggs, sour cream, buttermilk, oil, melted butter, brown and granulated sugar, and vanilla extract in a separate larger bowl. The mixture should look homogenous and smooth.
½ cup Dark Brown sugar, ¾ cup Granulated sugar, 2 Eggs, 1 tablespoon Vanilla extract, ¼ cup Butter, ⅓ cup Oil, 1¼ cup Pumpkin Puree, ⅓ cup Buttermilk, ¼ cup Sour cream
Add the dry ingredients to the wet ingredients, and using a rubber spatula, fold the dry ingredients in. Mix everything gently, and do not overmix.
Leave the batter on the counter to rest for 10-15 minutes. In the meantime, you can prepare the filling.