Preheat oven to 400°.
Place trimmed and halved brussels sprouts in a bowl; add pesto, olive oil, and garlic salt and toss.
Transfer sprouts to a baking sheet and roast 30-35 minutes.
Bring a pot of salted water to boil; add pasta and cook until al dente, 8-10 minutes.
While pasta is cooking, heat a sauté pan with butter over medium heat.
Add meatballs and occasionally turn until heated through.
Once cooked, drain pasta and add brussels sprouts, meatballs, and stir.
Garnish with shaved parmesan and enjoy!