Judi's Spinach and Cheese Appetizer

1 large package chopped frozen spinach, thawed and drained
3/4 Stick of butter
1 C milk
1 t. salt
1 T. baking powder
1 C flour
1 egg
1 C grated Monterey Jack cheese

In a large mixing bowl mix ingredients together. Pour into a greased baking dish. Bake 30 to 45 minutes at 350°.