Preheat oven to 350 degrees F (175 degrees C). Grease 2 mini donut pans with spray.
Whisk flour, baking powder, nutmeg, and salt together in a bowl.
2/3 cup all-purpose flour, 1/2 tsp baking powder, 1/4 tsp ground nutmeg or more to taste, 1/8 tsp salt
Stir milk and vanilla extract together in a separate bowl.
1/4 cup milk, 1/2 tsp vanilla extract
Beat butter and 1/3 cup white sugar together in a third bowl using an electric mixer until smooth and creamy; beat in egg.
5 tbsp softened butter, 1/3 cup white sugar, 1 egg
Alternate adding flour mixture and milk mixture into butter mixture about 1/3 at a time and mix with wooden spoon until batter is smooth.
Spoon batter into a piping bag and pipe into a mini donut pan about 2/3-full.
Bake in the preheated oven until a toothpick inserted in the center comes out clean, 8-10 minutes.
Mix sugar and cinnamon together in a bowl; add warm doughnuts and gently toss with hands until coated.
1/3 cup white sugar, 1 tsp ground cinnamon
Enjoy!
