4 tbsp. butter
3 eggs
1 c. flour
1 c. milk
1 tsp. salt
1 tsp. baking powder
1 lb. grated cheddar cheese
1 (10 oz.) pkg. frozen, chopped spinach, thawed & drained
1 sm. onion, chopped
1/2 c. chopped mushrooms (opt.)

In a 9"x13" pan, melt the butter. Mix remaining ingredients together and spoon into pan. Bake at 350 degrees for 35 minutes. Cool slightly before cutting into squares. Can be served hot or at room temperature or cold.