Preheat oven to 350ºF. Lightly grease a donut pan with baking spray that contains flour.
In a medium bowl, whisk together the flour, baking powder, ground cinnamon, ground nutmeg, and salt.
2 cups All-purpose flour, 2 tsp Baking powder, 1/2 tsp Ground cinnamon, 1/2 tsp Ground nutmeg, 1 tsp Kosher salt
In a separate large bowl, whisk the buttermilk, eggs, granulated sugar, melted butter, and vanilla until combined.
3/4 cup Buttermilk, 2 large Eggs, 3/4 cup Granulated sugar, 1/4 cup Unsalted butter, 1 tbsp Vanilla extract
Add the wet ingredients to the dry ingredients and mix just until combined, and no streaks of flour remaining. Don’t overmix.
Spoon or pipe the batter into the donut pan, filling each cavity about 3/4 full. Bake for 10–12 minutes, or until the donuts spring back lightly when touched and a toothpick inserted in the centers comes out clean.
Let them cool in the pan for 5 minutes, then carefully remove from the pan to a wire rack to cool another 3-4 minutes.
Place the powdered sugar in a large ziplock bag or shallow bowl. While the donuts are still warm, place one donut at a time in the sugar and toss to coat evenly.
1 1/4 cup Powdered sugar