Prepare cake as directed on package in loaf pan.
Allow cake to cool completely.
Cut cake into 10 even slices.
Line the bottom of an 8 in. (20 cm) sq. cake pan with plastic wrap.
Cover bottom of plastic-lined pan with five of the cake slices.
Crush blueberries; then stir in fructose.
Allow to sit at room temperature for 30 minutes.
Spoon half of the blueberries over the cake in pan.
Combine nondairy whipped-topping mix and water in a bowl.
Stir to mix.
Place beaters in the bowl and chill for 30 minutes.
Beat until thick and creamy, but not into soft peaks.
Spoon half of the whipped topping over the blueberries in the pan.
Cover with remaining cake slices.
Spoon remaining blueberries over cake.
Beat remaining whipped topping to soft peaks; then spread it over blueberries.
Chill thoroughly before serving.