Chocolate "Hideaway" Mousse
["1 (21.5 oz.) box Pillsbury brownie mix", "1/2 c. very hot tap water", "1/2 c. oil", "1 egg"]
["Combine brownie mix, hot water, oil and egg in large bowl. Beat 50 strokes by hand.", "Spread in a 15 x 10-inch jelly roll pan which has been greased and floured (line with wax paper; also grease and flour).", "Spread mix even in pan and bake at 350\u00b0 for 15 minutes.", "Cool on rack 5 minutes.", "Turn pan upside-down over cake rack and unmold.", "Gently pull off wax paper; cool."]
["brownie mix", "very hot tap", "oil", "egg"]