Sprinkle gelatin over 1/2 cup milk in a small bowl; set aside.
Place 4 cups milk and almonds in a blender, and process until smooth. Strain through a sieve into a medium saucepan; discard solids. Stir in sugar, salt, and extract, and bring to a boil. Add the gelatin mixture, stirring until gelatin dissolves; remove from heat.
Place pan in a large ice-filled bowl for 30 minutes or until milk mixture comes to room temperature; stir occasionally. Gently stir one-fourth of whipped topping into milk mixture; gently fold in remaining topping.
Spoon 2/3 cup milk mixture into each of 9 (6-ounce) custard cups coated with cooking spray. Cover and chill at least 4 hours or overnight. Loosen edges of blancmange with a knife or rubber spatula. Place a dessert plate upside down on top of each cup, and invert onto plates.