Preheat oven to 375°. Line a large rimmed baking pan with foil; spray with nonstick cooking spray; set aside.

Cook orzo in salted boiling water according to pkg. directions. Drain; reserve ½ cup pasta water. Set orzo aside; keep warm.

Pat cod dry with paper towels. Sprinkle with Italian seasoning and ¼ tsp. salt. Place cod, onion, 2 tbsp. parsley and 2 cloves garlic in a food processor. Cover and pulse until coarsely chopped. Transfer mixture in a large bowl. Add eggs, bread crumbs, ¼ cup cheese, potato starch, mayonnaise, 1 tbsp. lemon zest and 1 tbsp. vinegar. Gently stir until combined.

Shape fish mixture into balls using a 1¼-in. scoop or moistened hands. Place meatballs 1 in. apart on prepared baking pan; refrigerate for 15 to 20 minutes. Heat oil over medium-low heat in a large nonstick skillet; add meatballs. Cover and cook for 12 to 15 minutes over medium-low heat, turning once halfway. Remove cover and cook for 4 to 6 minutes more over medium heat or until meatballs reach at least 145°, turning often. Remove meatballs and drain on paper towels. Cool skillet slightly.

Wipe skillet clean. Heat butter and remaining 2 cloves garlic, chopped, in skillet over medium-low heat; cook for 1 to 2 minutes until melted. Add orzo, orzo water, remaining ½ cup cheese, cream, remaining 3 tbsp. vinegar and 2 tbsp. parsley; cook for 2 to 3 minutes over medium heat, stirring continuously.

To serve, divide orzo onto serving plates; top with meatballs. Garnish with additional parsley, cheese and lemon zest, if desired. Serve with lemon wedges. Season to taste with additional salt.