Preheat oven to 400 degrees F. Coat a 6-mold mini Bundt pan with cooking spray. Coat the molds with 1 1/2 tablespoons granulated sugar, tapping out the excess.Advertisement
Whisk flour, baking powder, baking soda, salt, cinnamon and nutmeg in a large bowl. Whisk egg, buttermilk, brown sugar, pumpkin, oil and lemon zest in another large bowl. Add the dry ingredients and stir until just combined.
Spoon about 1/4 cup batter into each mold. (You will use half the batter.)
Bake the doughnuts until puffed and browned, 14 to 15 minutes. Let cool in the pan for 5 minutes. Loosen the edges and invert the doughnuts onto a wire rack.
Clean the pan, and coat it with cooking spray and the remaining 1 1/2 tablespoons granulated sugar. Repeat steps 2-4 with the remaining batter. Serve the same day.
Make Ahead Tip: Hold at room temperature for 6 hours
Equipment: 6-mold mini Bundt pan