Broccoli Hamburger Casserole (Shelby Township, MI)

Ingredients
2 (16 ounce) packages frozen broccoli 2 pounds ground beef 1 (8 ounce) package fresh mushrooms 1 large onion, chopped salt to taste ground black pepper to taste 2 (10.75 ounce) cans condensed cream of celery soup 1 (16 ounce) container sour cream 1 (16 ounce) package shredded Monterey Jack cheese

Directions
Preheat oven to 350 degrees F (175 degrees C). Prepare the broccoli according to package directions.
In a skillet over medium heat, mix the ground beef, mushrooms, and onion. Cook until beef is evenly brown; drain grease. Season with salt and pepper, and mix in cream of celery soup and sour cream. Continue cooking until heated through. Transfer to a medium baking dish, and evenly layer with broccoli. Top with cheese.
Bake 1 hour in the preheated oven, until bubbly and lightly brown.