To make the keto meatballs, mix together the ground beef, Parmesan cheese, parsley, onion, garlic, paprika, salt, black pepper, and crushed red pepper flakes, if using, in a large bowl. Use your hands to shape the mixture into small balls, about the size of a golf ball.

Heat the olive oil in a large skillet over medium-high heat. Once the oil is hot, add the meatballs to the skillet and cook them for about 5-6 minutes, or until they are browned on all sides and cooked through.

Serve the keto meatballs hot, garnished with fresh parsley, if desired. Enjoy!