Tri-Level Brownies
["1 c. quick rolled oats", "1/2 c. flour", "1/2 c. brown sugar", "1/4 tsp. baking soda", "6 Tbsp. butter, melted", "3/4 c. sugar", "1/4 c. butter, melted", "1 (1 oz.) sq. unsweetened chocolate, melted and cooled", "1 egg", "2/3 c. flour", "1/4 tsp. baking powder", "1/4 c. milk", "1/2 tsp. vanilla", "1/2 c. chopped walnuts", "Fudge Frosting"]
["For bottom layer, stir together first 4 ingredients and 1/4 teaspoon salt.", "Stir in 6 tablespoons melted butter.", "Pat in a 11 x 7 1/2 x 1 1/2-inch baking pan.", "Bake at 350\u00b0 for 10 minutes."]
["rolled oats", "flour", "brown sugar", "baking soda", "butter", "sugar", "butter", "unsweetened chocolate", "egg", "flour", "baking powder", "milk", "vanilla", "walnuts", "Frosting"]