Place racks in the center and upper third of your oven. Preheat the oven to 425 degrees F. Line a large baking sheet with parchment paper.
Place the cauliflower on a cutting board and slice off the base so that if forms a flat surface. Cut away the thick green stems. Stand it up on it's end, with the florets-side up. Working from top to bottom, slice the head into 1-inch thick "steaks" (I recommend starting at the center, then working your way out). Some of the slices may break apart and florets on the sides will fall away. Arrange all of the cauliflower, both steaks and florets, into a single layer on the prepared baking sheet.
In a small bowl, stir together the oil, Italian seasoning, garlic powder, salt, and pepper. Brush over both sides of the cauliflower steaks and florets. Turn any loose florets so that their flat, cut sides are facing down and touching the surface of the pan.
Bake the cauliflower on the center rack for 20 minutes. Remove from the oven. With a thin, flexible spatula, gently turn the steaks and florets over. Sprinkle the Parmesan over the top. Return the pan to the oven and continue baking until the Parmesan turns golden and the cauliflower is tender and caramelized at the edges, 18 to 20 additional minutes. Remove the pan from the oven and turn the oven to broil.
While the cauliflower bakes, prepare any noodles you would like to serve with the cauliflower. If you'd like additional sauce to serve on the side with the noodles, warm it in a small saucepan over medium heat (reserve 1 cup sauce for baking the cauliflower).
Once the cauliflower has baked, spoon the 1 cup sauce over the top. Sprinkle with the mozzarella. Return the cauliflower to the oven, placing the pan on the upper middle rack. Broil until the cheese is melted and turning golden, 1 to 3 minutes. Do not walk away from the oven, to ensure the cauliflower does not burn. Sprinkle it with the basil. Enjoy immediately, with noodles and warmed sauce if desired.