PREPARATION:
- Melt 2 tablespoons butter in large skillet over medium heat. Add onion. Cook and stir 8 to 10 minutes or until onion is very soft. Remove from heat; set aside.
- Combine beef, veal, pork, bread crumbs, beaten eggs, 1/2 teaspoon salt, pepper and nutmeg in large bowl. Add onion; mix well. Using 2 tablespoons meat mixture per ball, shape into 36 meatballs or 1 tablespoon meat mixture for cocktail-size meatballs. Set aside.
- Preheat oven to 200°F. Reheat skillet over medium heat; add one fourth to one third of meatballs. (Do not crowd skillet.) Cook 8 minutes, shaking skillet to allow meatballs to roll and brown evenly. Reduce heat to medium-low. Cook 15 to 20 minutes or until cooked through. Transfer to covered casserole dish; keep warm in oven. Repeat until all meatballs are cooked.
- Combine milk, half-and-half, egg yolk and remaining 1/2 teaspoon salt in small bowl. Wipe out skillet. Melt remaining 2 tablespoons butter over medium heat. Whisk in flour. Stir well. Slowly stir milk mixture into flour mixture. Reduce heat to medium-low. Cook and stir 3 minutes or until thickened. Remove dish from oven and pour sauce over meatballs. Serve immediately.
