Blitz the cookies in a food processor or bash with a rolling pin, add the chocolate, sea salt and butter and blitz again until the mixture begins to bind together.

Tip crumb mixture into 9" flan/cake tin with removable base.

Press down crumb mixture, pushing up the sides of the tin to create biscuit walls.

Pop base into the fridge for at least an hour whilst you set to work on the filling.

Combine the cornflour and milk ensuring there are no lumps and flour has completely dissolved.

Add the chopped chocolate, cream, coffee, cocoa, vanilla, sugar, olive oil and salt to a saucepan and gently heat.

Once the chocolate has completely melted and the liquid has turned a dark colour, add the cornflour mixture.

Continue to stir, do not leave! The mixture will thicken quite quickly to a chocolate custard consistency.

Pour into a bowl and cover mixture with clingfilm or wet baking sheet, actually have the film touching the mixture to prevent a thick skin forming. Allow the mixture to cool for 20mins.

Once cooled pour into the biscuit base and return to the fridge for a couple of hours or overnight (mine was left overnight)

To decorate I finely grated some of the remaining dark chocolate over the top but you can decorate as you see fit.