Preheat the air fryer. Set it to 350°F (175°C) for about 3–4 minutes. A preheated basket helps the donuts brown evenly.

Prep the biscuits. Open the can and separate the biscuits. Use a small round cutter, the wide end of a piping tip, or even a bottle cap to cut a 1-inch hole in the center of each biscuit. Save the holes for donut holes.

Lightly oil the basket. Spray or brush a thin coat of oil on the air fryer basket or tray to prevent sticking. Avoid heavy spraying on the donuts themselves to keep the texture light.

Arrange and air fry. Place 3–4 donuts in a single layer, leaving space so air can circulate. Air fry for 5–6 minutes, flipping halfway through. They should be golden brown and puffed.

Air fry the holes. Cook the donut holes for 3–4 minutes, shaking the basket once. They brown faster, so keep an eye on them.

Brush with butter. While warm, brush the donuts lightly with melted butter. This helps coatings stick and adds that classic donut flavor.

Coat with cinnamon sugar. Stir sugar and cinnamon in a shallow bowl. Toss warm donuts to coat. For extra coverage, double-dip.

Make a quick glaze (optional). For vanilla: whisk powdered sugar, milk, vanilla, and a pinch of salt until smooth. For chocolate: whisk powdered sugar, cocoa, milk, vanilla, and salt. Dip warm donuts, let excess drip, and add sprinkles if you like.

Serve. Enjoy right away for the best texture. The contrast of warm dough and sweet coating is unbeatable.