In a large bowl, start by adding the crushed biscuits.
Add the crushed walnuts, the melted butter and mix everything very well until the butter is incorporated.
Then, add the refined sugar, the orange juice and mix again.
Divide this mixture into 2 equal parts and set one aside.
To the other one, add the semi-sweet chocolate and mix.
Transfer this chocolate mixture to a removable-bottom cake pan with a 20cm diameter.
Arrange it evenly until flat and set aside.
Then, coat the bananas with the ends cut off in some lemon juice and arrange them in the pan with the chocolate mixture.
Place the other half of the mixture we set aside on top of the bananas,
Arrange it evenly until flat and set aside.
In a large bowl, add the very cold heavy cream and beat with an electric mixer until it forms stiff peaks.
Add the whipped cream to the cake pan and spread it well.
Transfer the remaining whipped cream to a piping bag and remove the collar from the pan.
Take the dessert to the fridge and let it chill for at least 2 hours.
After this time has passed, decorate the dessert as you wish with the remaining whipped cream.
Serve.