This is the recipe that used to be on the side of the Lipton Onion Soup Mix box. I haven't seen it on the box for a while now, so decided to post it here so I'll always be able to find the recipe. It's easy and has great flavour.
In a large skillet, brown the ground beef in the cooking oil, adding the minced garlic after the meat is mostly browned. Drain excess fat. Add the soup mix, frozen veg, 1 1/4 cups milk, oregano, salt & pepper. Bring it all to a boil, then lower heat & simmer for 5 minutes. Turn the meat mixture into a 9x13 baking pan which has been lightly greased or sprayed with Pam. Meanwhile, peel & boil the potatoes til soft, then drain. Mash the potatoes, add the 1/4 cup warmed milk and 1 Tblsp. butter. Spread the potatoes over the meat filling to cover completely. Sprinkle with the grated cheddar. Bake at 350 degrees F for 30 minutes.