Crustless Spinach Quiche
["4 Tbsp. butter", "3 eggs", "1 c. milk", "1 c. flour", "1/2 tsp. salt", "1/2 tsp. baking powder", "2 pkg. frozen chopped spinach, thawed and squeezed to drain", "1 lb. grated sharp Cheddar cheese (or a mixture of Cheddar and Mozzarella)", "1/4 c. chopped onion"]
["Preheat oven to 350\u00b0.", "Melt butter in a 9 x 13-inch pan in oven; spread evenly over bottom of pan (and halfway up sides). Beat eggs; add milk, flour, salt and baking powder.", "Mix well. Stir in spinach, cheese and onions.", "Spoon into buttered baking pan.", "Bake for 35 minutes.", "Remove from oven and let stand for 45 minutes.", "Cut into squares.", "(Quiche will be relatively flat and quite firm in texture.)"]
["butter", "eggs", "milk", "flour", "salt", "baking powder", "spinach", "grated sharp", "onion"]