Prep the air fryer: Preheat your air fryer to 320°F (160°C) for about 3–5 minutes. Line the basket or tray with 6–8 paper muffin liners, or place silicone muffin cups inside.
Make sure they’re stable and not touching the heating element.
Mix dry ingredients: In a large bowl, whisk flour, sugar, baking powder, baking soda, and salt until evenly combined.
Blend wet ingredients: In a separate bowl, whisk milk, yogurt (or sour cream), melted butter, egg, and vanilla until smooth.
Combine gently: Pour the wet mixture into the dry ingredients. Stir with a spatula just until no dry streaks remain. Do not overmix—a few small lumps are okay.
Fold in chips: Gently fold in the chocolate chips. The batter will be thick and spoonable.
Fill liners: Divide the batter evenly among the liners, filling each about 3/4 full.
Sprinkle a few extra chips and coarse sugar on top for a bakery look.
Air fry: Cook at 320°F (160°C) for 10–13 minutes, depending on your air fryer and muffin size. Rotate the tray halfway through if your model has hot spots.
Check doneness: A toothpick inserted in the center should come out with a few moist crumbs, not wet batter. Tops should be lightly golden.
Cool briefly: Let muffins rest in the cups for 5 minutes, then transfer to a rack to cool.
Enjoy warm while the chips are melty.