Preheat your oven to 400°F and line a baking sheet with parchment paper.
In a large mixing bowl, combine the ground beef, egg, almond flour, minced garlic, chopped parsley, onion powder, salt, and pepper.
Gently mix the ingredients by hand until just combined, being careful not to overwork the meat to ensure a tender texture.
Roll the mixture into 1.5-inch balls and place them on the prepared baking sheet.
Roast the meatballs for 15-18 minutes until browned and cooked through to an internal temperature of 160°F.
While meatballs roast, heat the olive oil in a skillet over medium heat and briefly sauté the zucchini noodles for 2-3 minutes until just tender.
Warm the marinara sauce in a small saucepan over low heat.
Plate the zucchini noodles, top with the roasted meatballs, and drizzle with the warm marinara sauce.