Spinach Bars - cooking recipe

Ingredients

4 Tbsp. butter
3 eggs
1 c. flour
1 c. milk
1 tsp. salt
1 tsp. baking powder
1 lb. grated Cheddar cheese
1 small chopped onion
1 (10 oz.) pkg. frozen chopped spinach, thawed and drained
1/2 c. mushrooms, chopped (optional)

Preparation

In a 9 x 13-inch pan, melt the butter.
Mix remaining ingredients together and spoon into pan.
Bake at 350\u00b0 for 35 minutes.
Cool slightly before cutting into squares.
Can be served hot or at room temperature.