Donut Muffins

Preheat the oven to 350°F. Arrange a rack in the center of the oven. Lightly grease a 12-cup muffin pan.

Combine the dry ingredients: In a large mixing bowl, whisk together the flour, baking powder, nutmeg, salt, and baking soda.

Combine the wet ingredients: In another mixing bowl, whisk together the sugar, sour cream, butter, oil, eggs, and vanilla extract until smooth. Add the flour mixture to the sour cream mixture, and mix with a silicone spatula just until combined. Don't overmix.

Bake: Divide the batter evenly among the muffin cups. They should be about 3/4 full, depending on your pan. Bake until the tops are lightly golden around the edges and a toothpick inserted into the center of a muffin comes out clean, 20 to 24 minutes. Let the muffins cool in the pan for 5 minutes. Run a knife around the edges of each muffin to release them from the pan and place them on a wire rack to cool slightly.

Add the coating: As soon as the muffins are cool enough to handle comfortably, about 5 minutes, combine the sugar and cinnamon in a wide shallow bowl. Working with one muffin at a time, use a pastry brush to coat each muffin with the melted butter. Place each muffin in the cinnamon-sugar mixture, and turn to coat evenly. Serve warm or at room temperature. Store leftover muffins in an airtight container for up to 3 days.