In medium bowl, combine turkey, spinach, bread crumbs, onion, garlic powder, salt, egg product and 2 tablespoons of the mustard-mayonnaise sauce; mix well. Shape into about 45 (1-inch) balls.
Spray large nonstick skillet with nonstick cooking spray. Heat over medium-high heat until hot. Add spinach balls; cover and cook 8 to 10 minutes or until spinach balls are firm and centers are no longer pink, turning occasionally. Keep warm.
Pour remaining mustard-mayonnaise sauce into small microwave-safe serving bowl. Microwave on HIGH for 1 1/2 to 2 minutes or until thoroughly heated. Stir sauce. Serve hot spinach balls with sauce.