Place the egg yolks and the maple syrup into the bowl of a kitchen stand mixer with a beater attachment and beat until pale and thick (3-5 minutes).
Add the whipped cream and mascarpone cream and beat gently until combined.
In a separate, clean bowl add the egg whites and whisk until soft peaks form (this can be done in a kitchen stand or with a hand whisk).
Fold the egg whites into the cream mixture until no white streaks remain.
Cover the cream and place in the fridge for at least 2 hours to thicken.
This cake can be constructed in either a 5 or 6 inch spring form cake tin. I have used a 6 inch tin. It can also be made by cutting the cake into 3 long rectangular pieces to make a bar cake/slice.
Take the bottom of the chosen tin and cut 2 circles from the sweet potato sheet cake. Make sure at least 1 of the circles is complete. The scraps will be used to complete the 2nd circle (if needed) and form the 3rd, bottom layer. If making a bar cake cut the sheet cake into 3 long pieces.
Take a 6 or 5 inch spring form tin and line the bottom with baking paper. Line the sides of the tin, ensuring that the paper goes above the level of the tin edges (you can always add the 2 layer if needed during construction). Make sure the paper is greased.
Using the scraps of the cake, press the pieces into the bottom of the cake tin to fill the bottom of the spring form tin. It won't look pretty but it doesn't matter as there will be 5 layers on top and it will never be seen.
Combine the coffee and Marsala (or alternative) in a small bowl. Gently pour/spoon 1/3 of the mixture evenly over the cake.
Spread 1/3 of the mascarpone cream mix evenly over the bottom cake layer. Dollop and spread 1/3 of the caramel sauce over the cream and then evenly dust with 1/2 Tablespoon of Cocoa.
Top with a layer of cake (the almost full layer of cake; use more scraps to complete the layer) and evenly pour 1/3 of the coffee/Marsala over the cake and repeat the steps from the previous layer.
Place the full cake layer on top and evenly pour the remaining coffee/Marsala over the cake.
Cover the cake n plastic wrap and place the cake in the fridge for a minimum of 2 hours (overnight is better and up to 24 hours is ok). Remove the cake from the fridge and the tin and spread the remaining cream on the top and around the sides. Return to the fridge for a minimum of 30 minutes.
Make the ganache and gently spread it over the top of the cream. Allow the ganache to drip down the sides. Drizzle the remaining Caramel Sauce over the top of the cake and serve.
This amazingly awesome cake needs to be kept in the fridge between serves.