Preheat your oven to 400 degrees. Spray a regular-sized muffin pan with non-stick cooking spray and set aside.
In a large mixing bowl combine the egg, panko, garlic, onion, cumin, cayenne, oregano, cilantro, sumac, salt, and pepper.
Next, add the ground beef to the mixing bowl, using your hands gently incorporate the beef. Be careful to not overmix so the beef doesn't become dry.
Lightly press the spiced meatloaf mixture into each of the 12 muffin cups. Top the meatloaf muffins with 1/2 cup of marinara, dividing evenly amongst the 12 portions. Place the muffin pan on a rimmed baking sheet and bake for about 15 to 20 minutes or until internal temperature reaches 165 degrees.
Remove the muffin pan from the oven and garnish each meatloaf muffin with the crumbled feta. Serve and enjoy!