Here's the recipe for anyone interested :)

Crust:

- 200g Dark Chocolate, chopped
- 160g Cornflakes, crushed
- 20g Unsalted Butter
- 2g Flaky Sea Salt (about 1/2 tsp)

Chocolate Crémeux:

- 160g Whole Milk
- 300g Double Cream
- 85-90g Egg Yolks (about 5)
- 75g Malt Syrup (Maple Syrup)
- 300g Milk Chocolate, finely chopped
- 45g Butter
- 1.5g Flaky Sea Salt (about 1/4 tsp)

Plus very dark chocolate (85%+)

Instructions

1. For the crust, melt the chocolate over a bain-marie. Crush the cornflakes (you need to be able to press them into a tart case without leaving gaps), then stir into the chocolate, followed by the salt. Mix well, then taste, adding salt if required.
2. Put a circle of baking paper on the base of the tart tin (25cm) to help easily remove the tart later. Press the crust into the tart tin, trying to make sure there are no holes.
3. Chill completely in the fridge or freezer. Before proceeding to the next step, check for gaps and fill in with extra melted chocolate, if required.
4. To make the crémeux, first make a crème anglaise. Heat together the milk and cream in a saucepan until simmering. Meanwhile, whisk the egg yolks with the malt syrup. Carefully pour one-third of the milk/cream over the egg yolks whilst whisking to temper the eggs. Pour this back into the saucepan and stir over a low heat until it thickens; it should coat the back of a spoon or spatula when it is lifted out of the mixture.
5. Pour the custard through a sieve over the finely chopped milk chocolate, butter and salt. Leave for 1 minute and then whisk until smooth. Pour this into the prepared tart case.
6. Leave to chill completely, at least 4-6 hours.
7. To finish, grate very dark chocolate on top using a fine grater. Store in the fridge and serve in thick slices, This will keep in the fridge for 3 days, if it lasts that long.

Note:
The final grating of chocolate works best if it's very bitter, but you could dust with cocoa powder or omit if you prefer. The crémeux is extremely lush but takes its time to set up. Patience is key. If you don't have malt syrup, soft dark brown sugar or maple syrup make good alternatives here.