Pour hot water into a coffee mug or bowl, then mix in 2 packets of instant coffee until dissolved. Set aside to cool. You may also use concentrated brewed black coffee for this step.
Once cooled, dip half of the ladyfingers into the coffee for just 1 second (we don’t want it to be soggy).
Line dipped ladyfingers on the bottom of 8″x8″ baking dish.
In a large mixing bowl, combine light whipped topping, whey, vanilla extract, mascarpone cheese, and Stevia/Splenda to taste (optional) with electric mixer on high for about 10 seconds. Do not over-mix, as you want the consistency to remain as fluffy as possible.
With a spatula, spread half of this mixture over the ladyfingers. Repeat another layer of dipped ladyfingers and another layer of cream mixture on top.