Heat a skillet over medium high heat. Break the ground chuck into large chunks. Press it together firmly to help it hold it's shape making large meatballs. You can make them round, but I tend to leave mine in rounded rectangles. Season the meat liberally with salt, pepper, & garlic powder.
Place the meat in the center of the hot skillet. Spread the sliced onions around the outside perimeter of the skillet, & season with salt & pepper. Drizzle about 3 tablespoons of Worcestershire sauce over the meat & onions. Sear the meat on each side, only turning to brown another side. Push the meat & onions to one side of the skillet, tilting the skillet so that the pan drippings collect on the opposite side. Whisk in the flour, & cook for 1-2 minutes.
In a small bowl, mix together the brown gravy mix with the water & remaining 2 tablespoons Worcestershire sauce. Pour the mixture into the skillet & stir it into the meat and onion mixture. Cover & cook on low heat for 15 minutes, or until the meat is cooked through.