Preheat the oven to 425 degrees F (218 degrees C). Line a baking sheet with parchment paper or foil (grease if using foil).
In a large bowl, stir together the almond flour, grated parmesan, Italian seasoning, sea salt, and black pepper.
Whisk in the milk, grated onion, egg, garlic, and fresh parsley. Let the mixture sit for a couple of minutes.
Mix in the ground beef using your hands, until just incorporated. (Don't over-mix to avoid tough meatballs.)
Form the mixture into 1 in (2.5 cm) balls and place on the lined baking sheet.
Bake the keto meatballs for 10-12 minutes, until they are barely done. They should reach 155-160 degrees F. If you want them more golden, you can place them under the broiler for 1-3 minutes. Drain off any excess liquid. Top with marinara sauce, return to the oven, and bake for 3-5 minutes, until the sauce is hot and the meatballs are cooked through.
Stovetop instructions: Heat 1-2 tablespoons of olive oil in a large skillet over medium heat. Add the low carb meatballs in a single layer and fry for 2 minutes per side on different sides, until golden brown. Pour the marinara sauce over them, cover, and simmer for about 10 minutes, until cooked through.
