Spread the bottom of a springform pan (18 cm Ø) thinly with oil. Melt butter. Put 19 biscuits in a freezer bag and crumble them finely with a cake roll. Mix well with the melted butter.
Press the mass into the mould as a base. Chill for about 1 hour.
Soak gelatine in cold water. Peel the bananas, cut them into smaller pieces and puree them together with the lemon juice. Mix cream cheese, banana puree, peanut butter, sugar and vanilla sugar. Squeeze out the gelatine and dissolve in a small pot at very low heat.
First stir 2 tablespoons of cream into the gelatine, then stir everything into the rest of the cream. Pour the peanut-banana cream onto the biscuit base, smooth it down and chill for at least 4 hours, preferably overnight.
Whip 150 g of cream until stiff, and finally pour in the cream firming agent. Spread the cream on the cake and chill until serving.
Coarsely chop the chocolate and coconut fat. Put 50 g cream in a small pot and melt while stirring. Leave to cool for 15-20 minutes, stirring occasionally. Remove the cake from the tin. Break the remaining biscuits into large pieces and spread on top.
Add the chocolate sauce.