In a large mixing bowl, combine self-raising flour with sweetened Greek yogurt. Stir until it forms a soft, cohesive dough. Knead gently on a floured surface for about 2-3 minutes.

Divide the dough into two equal portions. Roll each into logs and cut into small pieces, about 8-12 grams each. Roll these into smooth balls.

Preheat the air fryer to 350°F (180°C) for 5 minutes. Brush the basket with oil to prevent sticking.

Toss the dough balls in melted butter and place them in the air fryer basket in a single layer. Air fry for about 5 minutes until golden.

Remove cooked donuts, brush with more melted butter, and roll in a cinnamon-sugar mix to coat evenly.