Place a rack in the center of the oven and preheat to 450ºF.

In a large bowl, combine olive oil with ground coriander, chili powder, cumin, onion powder and salt. Spread the sauce on the cauliflower on a baking sheet and stir to coat. Spread cauliflower in a single layer.

Grill cauliflower in oven until bunches are golden and crisp, about 25 minutes - stir halfway through.

In a large bowl, whisk lime juice with brown sugar and salt. Then add the red cabbage and fresh coriander to the bowl. Stir.

Spread lettuce leaves on a plate, garnish each with roasted cauliflower, cabbage mix, salsa  and avocado.