1. Place the biscuits and the dark chocolate into the bowl of your stand mixer and pulse until you have fine crumbs.
2. Melt the butter in the microwave for 30-40 seconds, before adding the biscuit crumb mixture.
3. Pulse again, until well combined.
4. Pour the mixture into a loose-bottomed tart tin and use the back of a spoon to spread it all over the bottom and sides of the tin.
5. Place the tart case into the fridge for around 30minutes to chill.
6. To make the tart filling, begin by chopping up the rest of the chocolate into fine pieces and place it into a heatproof bowl.
7. Transfer the double cream into a heatproof bowl or jug and heat in the microwave for around two minutes.
8. Pour the cream over the chocolate and leave to sit for around 2-3 minutes.
9. Use a wooden spoon to stir the mixture together until all of the chocolate has melted and the ganache is glossy and smooth. If you find you still have some chunks of chocolate at this stage, you can place the mixture back in the microwave to heat in 30 second increments, stirring well between each.
10. Pour the chocolate ganache into the tart case and place in the fridge to set for at least two hours, but ideally overnight.
11. Remove from the fridge and allow to stand at room temperature for around 30 minutes before serving.
This decadent dessert looks incredibly professional and polished, but it is actually deceptively easy to make! If you’re not so keen on dark chocolate, then why not try switching it for orange-flavoured milk chocolate instead (although this will be a lot sweeter)?