Put the unflavored gelatin and the sugar substitute into a mixing bowl.
Add 1/2 cup (125 mL) pineapple juice.
Meanwhile, in a small saucepan bring the pineapple juice to a boil.
Add the pineapple mixture all at once to the gelatin mixture, stirring to combine.
Stir in the whipped topping and extracts.
Coat an 8 in. (20 cm) sq. pan with non-stick vegetable cooking spray.
Pour the batter into the pan.
Chill until firm.