Toss the walnuts with the olive oil in a mixing bowl. Mix the rest of the ingredients together, then sprinkle over the nuts while tossing them in the bowl so that they get an even coverage.

Set the air-fryer to 160°C using the ‘Roast’ mode and transfer the coated nuts to the fryer basket. Roast for 6 minutes, giving the basket a shake halfway through.

Tip the walnuts onto kitchen paper and spread them out into a single layer. Leave to cool completely before serving or storing in an air-tight container.