Heat the air fryer on 160C for 2 mins. Mix the oil, yogurt, egg and milk in a large bowl, then fold in the sugar, flour and bicarbonate of soda and combine well. Fold in the blueberries, chocolate chips or dried fruit, if using. Spoon the mixture into silicone cases or an air fryer muffin tin filled with paper cases to three-quarters full. You should be able to make 6-8 muffins, but you may have to bake them in batches.

Place the cases or tin in the air fryer basket and cook for 12-15 mins until the muffins are golden brown and a skewer inserted into the centre comes out clean.