Preheat and prep: Set your oven to 400°F (200°C). Lightly grease a 9x13-inch baking dish or large oven-safe skillet with olive oil.

Sauté aromatics: In a small skillet, warm a splash of olive oil over medium heat. Cook the minced onion with a pinch of salt for 3–4 minutes until softened. Add garlic and cook 30 seconds more. Let cool slightly.

Mix the meatball base: In a large bowl, combine ground beef, ground pork, eggs, almond flour, Parmesan, parsley, Italian seasoning, red pepper flakes (if using), the cooled onion-garlic mix, 1 teaspoon salt, and 1/2 teaspoon pepper. Mix gently with your hands until just combined. Don’t overwork the meat or the meatballs will turn dense.

Form meatballs: Roll into golf ball–sized meatballs (about 1.5 inches). You should get around 18–24, depending on size.

Quick sear (optional but recommended): Heat a large skillet with a light film of oil over medium-high. Brown meatballs on two sides for 2–3 minutes to develop flavor. They don’t need to cook through. Transfer to the baking dish. If skipping the sear, just place raw meatballs directly in the dish.

Add sauce: Pour marinara over and around the meatballs, coating them well. Gently stir to nestle them in the sauce without breaking them.

Bake uncovered: Place the dish in the oven and bake for 18–22 minutes, until the meatballs are just cooked through (165°F/74°C in the center).

Add cheese: Sprinkle mozzarella evenly over the top. Add a dusting of Parmesan for extra flavor.

Finish baking: Return to the oven for 6–8 minutes, until the cheese is melted and bubbly. For golden spots, broil for 1–2 minutes, watching closely.

Rest and serve: Let the bake rest 5 minutes. Garnish with extra parsley and a grind of black pepper. Serve hot.