Preheat oven to 400°F (200°C). Line a baking sheet with parchment. In a large bowl, whisk almond flour, Parmesan, garlic, onion, Italian seasoning, salt, and pepper. Add turkey and egg, then mix gently with your hands until just combined, about 30 seconds.

Lightly oil your hands. Scoop 2 tbsp of mixture and roll into smooth balls, placing them on the prepared sheet. You will get about 20 meatballs.

Bake on the middle rack for 16 to 18 minutes, until an instant-read thermometer registers 165°F in the center.

Switch the oven to broil. Broil the meatballs for 1 to 2 minutes until deeply golden and crisp on top, then remove and serve with warm marinara sauce.