Remove the outer leaves from each cauliflower head. Cut off the bottom stem end so that you create a flat base and can stand the cauliflower up on a cutting board. Resting the cauliflower on the stem, use a large, sharp knife to trim away the sides, then cut the remaining head into 3-4 moderate "steaks." Reserve the sides for another use (we just grilled all the pieces, but you can also use the extra pieces of cauliflower for pickling).
Heat a grill to medium (about 350 degrees F). Brush one side of each cauliflower steak and the tomato slices with olive oil (you can also use garlic infused olive oil for some added flavor). Salt and pepper to taste. Place the veggies on the hot grill. Cover the grill and let cook for 5 to 6 minutes, until the bottom of the veggies begin to char. Flip the veggies over, then re-cover the grill and cook for 2-4 additional minutes, until the veggies are slightly charred on both sides.
Remove the tomatoes, then add the slices of mozzarella onto the cauliflower steaks. Cover to let the cheese melt - about 1 to 2 minutes.
Remove the cauliflower from the grill, then assemble; for each cauliflower steak, add 1-2 slices of grilled tomato, then 1-2 teaspoons of the Serious Foodie Calabrian Hot Pepper Relish. Garnish with lemon, basil, and freshly grated Parmesan.
