Cook, crumble, and drain the hamburger.
1 lb. ground hamburger, cooked and drained
Dice bread into small cubes and place onto a baking sheet. Toast the bread cubes in the oven at 350° for about 10 minutes. (This step is optional, so if you're in a hurry you don't have to toast the bread.)
1 1/2 quart diced bread cubes
Melt the butter and continue cooking it until browned (caramel in color). Browning the butter is also optional, but it does add some flavor.
5 - 6 Tbsp. butter
Finely chop the celery and onion and saute in the butter until softened.
3 ribs celery (3 stems of celery), chopped, 1 small onion, chopped
Whisk the eggs, milk, and seasonings. Add this to the butter/veggie mixture.
2 eggs, 1/2 c. milk, 1/2 tsp. seasoned salt or garlic salt, 1/2 tsp. ground black pepper
Pour the butter/veggie mixture over the bread cubes. Stir to mix.
Butter a casserole dish and put in a layer of the bread cubes. Add a layer of hamburger. Then repeat with another layer of bread cubes and hamburger.
Spread the can of mushroom soup over the top.
1 can cream of mushroom soup
Bake the casserole, covered, for 50 minutes at 350°. Remove the cover and continue baking for another 10 minutes.
Serve immediately.
Refrigerate any leftovers in an air-tight container for up to five days. Reheat and enjoy.