Prepare the cauliflower by chopping it into florets. Try to get them an even size, if possible, so they'll cook evenly.
Prepare the seasoning by combining all of the spices with the olive oil and mixing.
Toss the cauliflower florets with the oil seasoning mixture in a large bowl to try and coat the cauliflower well.You could alternatively use a spray bottle with cooking spray/olive oil and then toss with the dry seasonings.
Arrange the cauliflower florets in a single layer in the air fryer basket, leaving a little space between them (do this in batches if needed). If they're too close, they'll just steam rather than becoming crispy.
Cook the cauliflower in the air fryer for about 20 minutes at 400ºF/200ºC, giving the basket a shake halfway through cooking in order to flip the florets.
Depending on your preferred texture, you may want to adjust the cooking time slightly. A couple of minutes less will result in cauliflower that has more 'bite,' increase it by just 1-2 minutes, and it will become super crunchy.The first time you try this cauliflower air-fryer recipe, it's worth keeping a close eye on the cauliflower as it can burn quite easily (based on freshness, size of florets, etc.).
How To Store
To make ahead: you can toss the uncooked florets with the oils and seasonings then store them covered in the refrigerator for 2-3 days, ready to air-fry when needed. Leftovers: you can store any leftover air-fried cauliflower florets in an airtight container in the fridge for up to 4 days. To reheat pop them back in the air-fryer or oven until just warmed through - this will help them crisp back up slightly too. Freezing: you could also try freezing the cauliflower. Lay the florets on a tray and freeze until almost solid then transfer to a freezer-safe bag or container for up to 3 months. Thaw in the fridge before reheating in the oven or air-fryer.
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Notes
To adjust this to oven-roasted cauliflower: Bake them in the oven at 400ºF/200ºC for 20-25 minutes, flipping halfway through.
How to use the cauliflower leaves and stems? I like to save them in a bag in the freezer to use for vegetable stock. You can also shred them into stir-fries and add them to smoothies (as cauliflower is safe to eat raw).
Can you use frozen cauliflower? Yes, but it's best to allow it to thaw first; otherwise, the texture can become quite mushy.
For super-crispy results, you can use panko bread crumbs to coat the cauliflower. However, you'll then need an egg white (or chia egg) to acts as a binder. If doing so, first coat the florets in the egg, then the spices, and finally the panko.
You could omit the oil entirely: Roasted cauliflower in air-fryer doesn't actually require it. However, it won't be as good; it will be drier and not as crisp.