Preheat and prep: Heat your oven to 400°F (200°C). Lightly grease a 9x13-inch baking dish with olive oil.
Mix the meatballs: In a large bowl, combine ground beef, ground pork, eggs, almond flour, Parmesan, onion, garlic, parsley, 1 tsp salt, 1/2 tsp black pepper, and a pinch of red pepper flakes if using.
Mix gently until just combined.
Shape: Roll the mixture into golf ball–sized meatballs (about 1.5 inches). You should get roughly 20–24 meatballs.
Quick sear (optional but recommended): Heat a large skillet with 1 tbsp olive oil over medium-high heat. Brown meatballs on two sides for 2–3 minutes total.
You’re not cooking through—just adding flavor and structure. Transfer to a plate.
Layer the dish: Spread 1 cup marinara in the baking dish. Nestle the meatballs in a single layer.
Spoon the remaining marinara over the top.
Bake: Cover loosely with foil and bake for 15 minutes. Remove foil, sprinkle mozzarella and a little extra Parmesan over the meatballs.
Finish baking: Return to the oven uncovered for 10–12 minutes, until the cheese is melted and bubbling and the meatballs read 160–165°F in the center.
Broil for color: If you like a golden top, broil on high for 1–2 minutes. Watch closely to prevent burning.
Rest and serve: Let stand for 5 minutes.
Garnish with extra parsley. Serve with zucchini noodles, roasted broccoli, or a simple Caesar salad.