Combine pork, onion, and cheese with a fork, then use a fork to stir in the eggs, spinach, pesto, salt and pepper so that the ingredients are evenly mixed. Add enough bread crumbs so that the meat barely holds together and stir in with the fork.
Use a small ice cream scoop to portion meatballs onto a baking sheet lined with a nonstick baking mat. Bake at 350 degrees until cooked through and browned, about 15-20 minutes. Drain off fat and drain meatballs on paper towels briefly before serving with Romesco Sauce for dipping.
Recipe by Cooking With MicheleĀ® at https://cookingwithmichele.com/2012/12/pork-pesto-and-spinach-meatballs-with-romesco-sauce/