1. Place the semolina and 1/2 cup of the milk into a medium bowl. Mix well into a smooth paste. Then, gradually add the rest of the milk, vanilla extract, and caster sugar. Mix thoroughly.
2. Transfer to a baking dish that can fit into the Air Fryer basket. Cook for 15-20 minutes at 300 F (150 C).
3. You can serve this semolina pudding either warm or cold. Enjoy.