1Mix flour with baking powder, salt and sugar in a bowl.
2Beat egg with milk in another bowl, then pour over dry ingredients and mix until thick, smooth batter.
3Gently fold in raisins and apple cubes.
4Preheat air fryer to 180°C (350°F) for 5 minutes.
5Using two spoons, form small dough balls and place in air fryer basket in a single layer, not touching.
6Cook for 10 minutes at 180°C (350°F), shaking basket halfway for even browning.
7Check if done: oliebollen should be golden and crispy. If needed, cook 2-3 more minutes.
8Carefully remove from air fryer, let rest 2 minutes, then dust with powdered sugar and serve warm.