I've made this for years and love it. Sandwichs next day (or two) are amazing,.
Mix an egg, some crushed Ritz crackers, a pkg of dried onion soup and several "dashes" of Worchester sauce in with the hamb. (If you are making a "huge"one, you may need more egg, etc.). Shape and place in whatever you are going to bake it in. Meanwhile mix 1 or 2 cans of cr. of mushroom soup with about 1/2 to 1 can of water. Pour over the top. Bake at 350 until done. AWESOME mashed potatoes and gravy the first night, leftovers the 2nd, and yummy sandwhiches if there is any left....