No-cook summer cake

Too hot to turn on the oven ? Make this delicious refreshing summer cake !
For the record, it's so easy to make that I was able to put this together in a hotel room!
My kind of backing ;-)

Ingredients

Ready-made sponge cake (I used three layers here)
250g of mascarpone
1 can of sweetened whipped cream (250 mL)
1 jar of rasberry jam (350 g)
About 500 g of fresh mixed berries (I used strawberries and blueberries)
Optional: Toasted hazelnuts

Assembly
If required, cut the sponge cake in even layers. Mix the mascarpone with some whipped cream, so that it becomes spreadable. If using large berries, cut them in slices.
Spread the first cake layer with jam, top with the mascarpone mixture, sprinkle with hazelnuts, top with fruits and add the next cake layer. Jam - mascarpone - hazelnuts - fruit and on to the last layer, where it's nice to pay a little more attention to the layout of the berries. If making this in advance, make sure to keep a little whipped cream to refresh the look of the cake before serving.

Enjoy!