Preparation

1. Mix the crushed rusks with the Nutella. Transfer to a bowl, add the powdered sugar, cocoa powder, and a pinch of salt, and mix thoroughly. Pour in the melted butter and mix again until a moist mixture forms.
2. Pour the mixture into a 22 cm tart pan. Press firmly into the bottom and sides, smoothing the surface with a spoon or the back of a glass. Refrigerate the base for about 20 minutes to harden.
3. Spread the fudge mixture evenly over the chilled base, spreading it evenly over the entire surface.
4. Peel the bananas and cut them into thick slices. Drizzle with lemon juice, mix gently, and then arrange on top of the fudge layer.
5. Start whipping the well-chilled cream. When it thickens slightly, add the powdered sugar and cream fixer mixture and continue beating until a thick cream forms.
6. Place the whipped cream in a piping bag fitted with a decorative tip and decorate the top of the tart. Sprinkle with grated dark chocolate.