Preheat the oven to 350°F. Spray a casserole dish with a non-stick spray.

Steam the broccoli, about 10 minutes, or until tender. In the meantime, melt the butter in a medium skillet over medium heat & sauté the celery, mushrooms, & onions for about 10 minutes, or until softened.

Drain. Combine the broccoli, & the cooked vegetables in a bowl.

Heat the mushroom soup & softened cheese in a saucepan over low heat until the cheese melts. Pour it over the broccoli mixture. Add the garlic salt, & black pepper. Combine.

Put in the prepared casserole dish & bake for 20 to 25 minutes. Sprinkle the top with the grated cheddar cheese the last 5 minutes of baking.