Cut the strawberries in half and slice the bananas. Moisten a large mixing bowl with a small amount of water or line it with plastic wrap so that it will be easier to get the cake out of the bowl later. Line the bowl with the sliced fruit, alternating between rings of strawberries and bananas, starting from the bottom and finishing at the top.
For the mascarpone cream, stir together the warmed mascarpone, softened butter, chopped almonds, powdered sugar, and vanilla extract in a large mixing bowl until combined. Once everything is combined, carefully fold in the whipped cream. If you'd like the mascarpone cream to hold more effectively, dissolve 1 tbsp of unflavored gelatin powder in a small amount of water and gradually stir it into the mixture.
Spoon ¾ of the mascarpone cream into the fruit-lined bowl and use a ladle to make a large well in the center. Transfer the bowl to the refrigerator and let it chill for 1 hour.
Once the cake has cooled, remove the mixing bowl from the refrigerator and pour Nutella into the well in the center.
Spoon the remainder of the mascarpone cream on top of the Nutella, then carefully spread it around evenly so that the Nutella is covered. Press the Ferrero Rocher chocolates into the mascarpone cream, transfer the cake to the refrigerator, and let it chill for at least 4 hours, preferably overnight.
Once the cake has chilled, carefully flip it over onto a serving plate and dig in!