In a large bowl, add the ground beef, well drained ricotta cheese, egg, breadcrumbs, Parmesan cheese, parsley, and lemon zest, and season generously with sea salt and black pepper. Mix to combine all the ingredients.
Lightly oil your hands, take off a small piece of the mixture and gently roll it between your hands to form 1-inch (2½-cm) meatballs (about 1 full tablespoon each).
Place the flour in a bowl, and roll each meatball into flour, shake the flour in excess and arrange them on a baking tray covered with parchment paper.
Heat the extra-virgin olive oil in a large frying pan over medium heat. Fold in the meatballs and leave them undisturbed until they are brown on one side. Shake the pan to loosen the meatballs, then turn each one with kitchen tongs and cook them on the other side for 4-5 minutes.
Remove the meatballs from the pan, and arrange them on a plate covered with paper towels to absorb the oil in excess. Transfer the meatballs to a large serving plate and serve, or mix them with tomato sauce and serve with pasta.
