In medium nonstick saucepan, combine sugar, cocoa, cornstarch and salt; mix well. With wire whisk, stir in milk. Cook over medium heat until mixture comes to a boil, stirring constantly with wire whisk. Boil 1 minute, stirring constantly. Remove from heat; stir in almond extract. Pour into 13x9-inch pan. Cover surface with plastic wrap. Place in freezer for 15 to 20 minutes or just until cool.
Place chocolate mixture in medium bowl; fold in whipped topping. Serve immediately or refrigerate until serving time. Store in refrigerator.