Dissolve lime gelatin in boiling water in a bowl.

Refrigerate the gelatin mixture until it begins to thicken, about 35 minutes.

Cut angel food cake into 1-inch cubes.

Place cake cubes in a 13x9x2 inch dish coated with non-stick spray and set aside.

In a small mixing bowl, beat reduced-fat cream cheese until smooth.

Beat in sugar and lemon juice until combined.

Add the partially thickened gelatin mixture to the cream cheese mixture and beat until well combined.

Fold in 1 1/2 cups of fat-free whipped topping.

Spread the cream cheese mixture evenly over the cake cubes in the dish, covering them completely.

Refrigerate the dish for at least 2 hours to allow the dessert to set.

Cut the dessert into squares.

Top each square with the remaining whipped topping before serving.