Savory Salisbury Steak

Can you picture it now?  Two oval ground beef patties swimming in brown gravy in their own compartment to prevent the gravy from mixing onto a section of mashed potatoes and maybe some corn or peas and carrots.  A frozen meal for a kid from the 70's who might have thought it was a treat to have a TV Dinner.
This is a great weeknight option - if you stay out of the Frozen Food aisle.  

Ingredients:
1/2 cup milk 7 Tbsp. instant potato flakes  1 lb. lean ground beef 1/4 cup onion, minced 2 Tbsp. parsley, chopped 1 egg 1 Tbsp. beefy-onion soup mix 1 tsp. Worcestershire sauce 4 Tbsp. unsalted butter 1 onion, halved and sliced thin 1 lb. white mushrooms, trimmed and sliced thin 1 Tbsp. tomato paste 2 Tbsp. all-purpose flour 1-3/4 cup beef broth 1/4 cup dry red wine Directions:

1. Whisk milk and potato flakes in a large bowl.  Add beef, salt and pepper to taste, minced onion, parsley, egg, beefy-onion soup mix and Worcestershire sauce and mix until combined.  Shape into four 1/2-inch oval patties and transfer to plate.  Refrigerate for at least 30 minutes or up to 4 hours.
2. Melt 1 Tbsp. butter in a 12-inch non-stick skillet over medium-high heat.  Cook patties until well browned on each side, about 10 minutes.  Transfer to plate.
3. Add onion and remaining 3 Tbsp. butter to now-empty skillet and cook until onion is softened, about 5 minutes.  Add mushrooms and 1/2 tsp. salt and cook until liquid has evaporated, about 7 minutes.  Stir in tomato paste and flour and cook until browned, about 2 minutes. Slowly stir in broth and wine and bring to a simmer.  Return patties to skillet, cover, and simmer over medium low heat until cooked through, 15-20 minutes.  Season sauce with salt and pepper to taste.
4. Serve with mashed potatoes, buttered egg noodles or rice.