Preheat the air fryer: Set it to 350°F (175°C). Lightly spray the basket with oil to prevent sticking.

Mix dry ingredients: In a large bowl, whisk flour, sugar, baking powder, salt, and nutmeg or cinnamon (if using). This distributes the leavening evenly.

Mix wet ingredients: In a separate bowl, whisk milk, yogurt (or sour cream), melted butter, and vanilla until smooth.

Combine to form dough: Pour the wet mixture into the dry. Stir with a spatula just until a soft dough forms. It should be slightly tacky but not wet. Avoid overmixing.

Turn out and knead lightly: Dust your work surface with flour. Gently knead the dough 3–4 times to bring it together. Pat or roll to about 1/2 inch thickness.

Cut donuts: Use a donut cutter, or a 3-inch round cutter and a small 1-inch cutter for the holes. Gather scraps and re-roll once if needed.

Prepare for air frying: Place donuts and holes in the basket in a single layer with space between. Lightly mist the tops with oil. Work in batches if necessary.

Air fry: Cook for 6–8 minutes, flipping halfway. Donuts should be golden and set. Donut holes may cook faster—check at 5–6 minutes.

Add toppings: Cinnamon sugar: Mix sugar and cinnamon. Brush warm donuts lightly with melted butter and roll in the mixture.

Vanilla glaze: Whisk powdered sugar, milk, vanilla, and salt until smooth. Dip warm donuts and let set on a rack.

Chocolate glaze: Whisk powdered sugar, cocoa, milk, vanilla, and salt. Dip tops and add sprinkles if you like.

Serve: Enjoy warm for the best texture. They’re especially good within the first few hours.