Ingredients
2/3 cup all-purpose flour
1/2 teaspoon baking powder
1/4 teaspoon ground nutmeg, or more to taste
1/8 teaspoon salt
1/4 cup milk
1/2 teaspoon vanilla extract
5 tablespoons softened butter
1/3 cup white sugar
1 egg
Coating:
1/3 cup white sugar
1 teaspoon ground cinnamon
Preheat oven to 350 degrees F (175 degrees C). Grease miniature muffin cups or line with paper liners.
Whisk flour, baking powder, nutmeg, and salt together in a bowl. Stir milk and vanilla extract together in a separate bowl. Beat butter and 1/3 cup white sugar together in a third bowl using an electric mixer until smooth and creamy; beat in egg.
Stir flour mixture, alternating with milk mixture, into butter mixture until batter is smooth. Spoon batter into a piping bag and pipe into muffin cups, about 2/3-full.
Bake in the preheated oven until a toothpick inserted in the center comes out clean, 10 to 12 minutes.
Mix 1/3 cup white sugar and cinnamon together in a bowl; add warm doughnuts and gently toss with hands until coated.