Preheat the oven to 375 degrees F (190 degrees C).
Place the Cauliflower (1) in one layer on a sheet pan. Toss with Extra-Virgin Olive Oil (3 tablespoon), Kosher Salt (3/4 teaspoon) and Ground Black Pepper (1/2 teaspoon)
Bake for 20 to 30 minutes, until the cauliflower is caramelized, tossing twice during baking.
Meanwhile, make the pesto. Place Hazelnuts (1/3 cup), Garlic (1 clove), Italian Flat-Leaf Parsley (2/3 cup), Kosher Salt (1/2 teaspoon) and Ground Black Pepper (1/2 teaspoon) in the bowl of a food processor fitted with the steel blade.
Process until the mixture forms a thick paste, about 1 minute. Add the Pecorino Romano Cheese (5 tablespoon) and pulse until combined. With the food processor running, slowly pour in Extra-Virgin Olive Oil (to taste) until desired consistency is reached.
Add Hazelnuts (2 tablespoon) and pulse until hazelnuts are roughly chopped.
Spread pesto on a serving platter and spoon the cauliflower on top. Serve hot. Enjoy!