Pre-heat your oven to 375F.
Spread the florets on a baking sheet. Drizzle olive oil and toss to coat the cauliflower.
Roast about 30-35 minutes. You want them soft, not mushy. They will cook a little more in the gratin.
While the cauliflower roasts, heat a frying pan over medium low heat.
Add 1 Tbsp olive oil and cook the shallots/onions until soft.
Add the garlic, chili flakes and anchovy paste if you are using it and cook one minute more.
Toss the roasted cauliflower, onion mixture, parsley, olives and 1/2 cup of pecorino romano in a large bowl.
Combine the shredded friulano and the remaining pecorino.
Transfer to a shallow oven proof baking dish, spread the cheese mix and olives overtop and cook for 25-30 minutes. You want the cheese nicely browned and the cauliflower tender.