Preheat oven to 450°. Gently stir together ground chuck, next 6 ingredients, and 3/4 cup chopped onions. Shape into 1-inch balls; place in a lightly greased (with cooking spray) 9- x 13-inch baking dish. Bake 20 minutes. Remove from oven, and drain off excess fat.
Heat butter in a large skillet over medium heat; add remaining onions, and sauté 4 to 6 minutes or until tender. Whisk in flour; cook, whisking constantly, 1 minute. Gradually whisk in beef broth, and cook, whisking constantly, until smooth. Stir in wine and next 4 ingredients. Reduce heat to low, and cook, stirring often, 15 minutes. Add meatballs, and simmer, stirring occasionally, 5 minutes.
We tested with Swanson 100% Natural 50% Less Sodium Beef Broth.