PREPARE pesto by adding all of its ingredients into a food processor. Process until pepitas are ground. Aim to have some texture and not making it completely smooth. Set aside.
BOIL 1 liter of water and place shaved Brussel Sprouts into a colander. Pour boiling water on top to blanch. Immediately after, run cold water over the Brussel Sprouts. Drain completely and transfer to a bowl.
SEASON Brussel Sprouts with olive oil, balsamic vinegar (if using), garlic powder, salt and pepper. Toss to combine. Set aside.
PREHEAT oven to 350ºF and line a baking sheet with parchment paper.
PREPARE Simple Mills pizza dough according to instructions on the box, forming a rectangle with the dough. Bake for 10 minutes.
REMOVE from the oven and garnish with pesto, 1/3 cup of shredded mozzarella and Brussel Sprouts. Bake for another 15 minutes.
REMOVE from the oven and garnish with parmesan shavings and chili flakes, if desired.