In a mixing bowl, combine the yogurt and egg.
Gradually mix in the flour until you achieve the desired consistency, adding more flour if the mixture seems too wet.
Stir in the lemon zest and sugar until well incorporated.
Preheat the air fryer and lightly coat the basket with oil to prevent sticking.
Spoon the mixture into the air fryer basket, making sure not to overcrowd it.
Cook in the air fryer for about 11 minutes, or until the donuts are fluffy and fully cooked.
