Preheat the air fryer to 200°C (390°F).

Lightly spray the air fryer basket with olive oil.

Add raw walnuts in a single layer, then spray a little more oil over the top.

Air fry for 5 minutes, shaking or stirring the basket halfway through for even roasting.

Remove and spread the roasted walnuts on a baking sheet.

Let cool for 5–10 minutes before eating or using in recipes.