Preheat oven to 375°F (190°C).

In a large bowl, combine 1/2 can of cream of mushroom soup, ground beef, bread crumbs, beaten egg, chopped onion, and salt.

Mix thoroughly until well combined.

Shape the mixture into an 8 x 4-inch loaf.

Place the loaf in a shallow baking pan.

Bake for 1 hour and 15 minutes.

While the loaf is baking, prepare the topping.

In a saucepan, blend the remaining 1/2 can of cream of mushroom soup with water and 2-3 tablespoons of drippings from the baking pan.

Heat the mixture over medium heat until warmed through.

After the initial baking time, pour the soup mixture over the meatloaf.

Return the meatloaf to the oven and bake for an additional 15 minutes, or until the topping is bubbly and slightly browned.