Heat oven to 180C/160C fan/gas 4. Line the base of a 23cm springform tin with baking parchment. Place the bourbon biscuits in a food processor and blitz until reduced to fine crumbs. Mix the melted butter and biscuit crumbs together, then press firmly onto the base of the tin with the back of a spoon. Bake in the oven for 10 mins then leave to cool while you make the filling.
Turn oven temperature up to 240C/220C fan/gas 9. In a large bowl beat the cream cheese and sugar with an electric whisk until creamy, then add in the cocoa, vanilla, coffee, eggs, soured cream and the melted chocolate and whisk again until smooth.
Brush the sides of a cake tin with a little more melted butter then pour in the cheesecake mixture and smooth the top with a spatula. Bake for 10 mins, then turn the heat down to 110C/90C fan/gas 1/4 for 25-30 mins. When ready the filling should be set, but with a little wobble in the middle. Turn off the oven, but leave the oven door open and allow it to cool in there for 2 hrs. Chill until ready to serve.
To decorate the cheesecake, carefully remove it from the tin and removed the lining paper from the base. Lightly whip the double cream and place or pipe 4 large dollops of it on top of the cheesecake in a ring with 4 smaller dollops in between. Top each mound of cream with a smaller splodge of passion fruit curd and then top with the cream egg halves then place the whole ones in between. Serve immediately.