Heat meatballs according to package directions. Meanwhile, in a bowl, whisk eggs, 3 tbsp. cold water and 1/4 tsp. salt. In a nonstick skillet, heat EVOO over medium. Add egg mixture, then meatballs and tomatoes. Cover and cook until eggs are set at edges, about 6 minutes. Tilt pan, letting uncooked eggs run underneath the set eggs. Cover and cook until frittata is just set, about 3 minutes. Remove from heat. Let stand, covered, 3 minutes. Transfer to a platter, cut into wedges and sprinkle with parsley.