1 (16 oz.) box powdered sugar, sifted
1/4 tsp. salt
1/3 c. milk
1/2 stick (1/4 c.) butter

Mix all in casserole. Microwave on high 2 minutes or until butter is melted. Stir vigorously until smooth. Add 1 cup peanut butter. Stir well. Pour into 10 x 6 x 2 inch buttered baking dish. Allow to cool and cut.