Preheat the air fryer to 160°C for 2 minutes. In a large mixing bowl, whisk together the egg, milk, yogurt, and vegetable oil until well blended. Gradually incorporate the sugar, flour, and bicarbonate of soda, stirring until the batter is smooth. Gently fold in your chosen mix-ins, whether blueberries, chocolate chips, or dried fruit. Spoon the batter into silicone muffin molds or an air fryer-compatible muffin tin lined with paper cases, filling each to about three-quarters of its capacity. Depending on mold size, this recipe yields approximately 6–8 muffins, which may require batch cooking.