Bring a large pot of water to a rapid boil over high heat. Season the water with 1 tsp of sea salt. While waiting for the water to boil, trim the cauliflower head, removing the stems and leaves. Cut the cauliflower into large quarters.
Add the cauliflower to the water and blanch for five minutes. Remove the cauliflower with a slotted spoon and place it on the air fryer.
Next, mix harissa, lemon juice, garlic, and salt and pepper in a small bowl. Pour the harissa sauce over the top of the cauliflower.
Place the cauliflower in the air fryer at 350 degrees for 15 to 20 minutes until the cauliflower is crispy and golden.