Coarsely grate a third of the cauliflower and set aside in a bowl. Break the remaining cauliflower into florets, roughly 1 1/4 inches/3cm wide, and add these to a separate bowl with the cauliflower leaves, if you have any, and the onion. Toss everything together with 2 tablespoons of oil and 1/2 teaspoon of salt, then spread out on a large parchment-lined baking sheet. Roast for about 20 minutes, until cooked through and golden brown. Remove from the oven and set aside to cool.
1 extra large cauliflower, 1 small onion, 80 ml olive oil, sea salt
Once cool, put the roasted vegetables into a large bowl with the 3 tablespoons/50ml oil, the grated cauliflower, and parsley, mint, tarragon, pomegranate seeds, pistachios, cumin, and lemon juice, along with 1/4 teaspoon salt. Toss gently, just to combine, then transfer to a platter and serve.
• The headnote states that if you want to get ahead, roast the cauliflower up to 4-6 hours in advance. Keep at room temperature and then just combine with the remaining ingredients when ready to serve.