Preheat the oven to 425 degrees F (220 degrees C). Brush a baking sheet with olive oil or line with parchment paper.
To prep the Cauliflower steaks, remove and discard the leaves and cut the Cauliflower (1/2 head) into 1-inch thick slices. (You can also roast the extra crumbles that fall off the steaks)
Place the cauliflower steaks on the baking sheet and brush them with Olive Oil (to taste). You want the surface just lightly coated. Season with Sea Salt (to taste) and Ground Black Pepper (to taste).
Roast the cauliflower steaks for 15-20 minutes, until the tops are browned and the edges are crispy. Check the Cauliflower halfway through and rotate your pan to ensure that all of the steaks are cooked evenly.
Meanwhile, put the Fresh Basil Leaf (2 cup), Parmesan Cheese (1/2 cup), Almonds (1/4 cup), and Olive Oil (2 tablespoon) in a food processor or blender, and season with Sea Salt (to taste) and Ground Black Pepper (to taste). Blend until you have a thick, finely chopped pasted.
Spread a generous amount of pesto on top of each cauliflower steak, and top with Mozzarella Cheese (1/2 cup).
Return to the oven and bake until the cheese melts and begins to bubble, 2-3 minutes. If you want crispy cheese, turn on the broiler for 1-2 minutes.
Serve the cauliflower steaks immediately with sides or main dish of choice.