Preheat your oven to 450°F
Remove the leaves and stem from the cauliflower and cut it length-wise into "steaks".
Whisk together the Colavita Olive Oil, 3 tbsp of the mustard, 1/2 tsp salt and black pepper into a small bowl.
Line a baking sheet with parchment paper and place the cauliflower on top. Using a pastry brush, baste the cauliflower with the olive oil and mustard mixture, coating both sides.
Roast for about 25-30 minutes until the cauliflower starts to turn dark brown and crispy. Remove from the oven.
Meanwhile, combine the parsley and Parmegiano Reggiano cheese in a bowl.
Coat the cooked cauliflower with the remaining mustard and sprinkle with the herb and cheese mixture.
Serve immediately with lemon wedges and extra herbs and cheese (if desired).