Preheat your oven to 350°F (175°C) and grease a 9x13-inch casserole dish with butter.

In a large skillet, cook 1 pound of ground beef over medium heat until browned, about 5–7 minutes, seasoning with salt and pepper.

In a food processor, blend 6 oz. of softened cream cheese until smooth, then incorporate 3 eggs one at a time.

Combine the cooked ground beef and the cream cheese blend in a large bowl, stirring until well integrated.

Sauté 5 cups of sliced mushrooms in 2 tablespoons of butter over medium heat for 5–7 minutes until soft and golden, seasoning with salt, pepper, and dried parsley.

Spread the beef-cream mixture in the greased casserole dish, layer with sautéed mushrooms, and sprinkle with grated cheese if desired.

Bake for 20–25 minutes until the edges are golden brown and the center is set.

Let the casserole cool for 5–10 minutes before slicing.