Preheat your oven to 400°F and line a rimmed baking sheet with parchment paper.
In a large mixing bowl, combine the ground beef, egg, almond flour, garlic powder, onion powder, oregano, sea salt, and black pepper.
Use your hands to gently mix the ingredients until just combined, being careful not to over-mix which can make the meatballs tough.
Scoop and roll the mixture into approximately 8-10 meatballs, each about 1.5 inches in diameter, and place them on the prepared baking sheet.
Bake the meatballs for 12 to 15 minutes until they are browned on the outside and cooked through to an internal temperature of 160°F.
While the meatballs are baking, add the marinara sauce to a large skillet and warm it over medium-low heat until simmering.
Transfer the cooked meatballs directly from the oven into the skillet with the warm sauce and toss gently to coat.
Serve the meatballs hot, garnished with freshly chopped parsley for a bright finish.