Roly’s Chocolate Biscuit Cake
First I should explain the theory behind chocolate biscuit cake (for those untutored in these matters): melt lots of chocolate, add in some broken digestive biscuits , leave to set. Couldn’t be simpler, really. If you’re in the US and don’t know what a digestive biscuit is, think graham cracker .
This recipe below is the Roly’s Bistro  version, taken from my recently acquired Zest! cookbook . The original recipe topped the chocolate/biscuit mixture off with some chocolate icing. I skipped that part, however, figuring that I already had quite enough chocolate to be going on with. Instead, I sprinkled some nice salt  on top of the biscuit cake and that was a fine addition.
As you can see, this contains a humungous amount of chocolate. The original recipe stated that this amount would make dessert for 10-12 people. I would say that you could feed many more than that, as it is unashamedly rich. You could easily make half this amount and still keep yourself in chocolate biscuit cake for days. The other thing to say, of course, is that because this is mostly just chocolate, the quality of the chocolate really matters. I used a mixture of Lindt and Green & Black’s chocolate bars for this.
- If you cut the slab into pieces measuring roughly 3cm x 3cm, you’ll get around 45 little chocolate biscuit cubes; takes approx. 20 min to prep + 2 hours to set
- 400g milk chocolate
- 250g dark chocolate
- 200g white chocolate
- 150g unsalted butter
- 275g golden syrup
- 275g digestive biscuits
- some good quality salt, such as fleur de sel, to sprinkle on top (optional)
You’ll also need:
- A large heatproof bowl for melting the chocolate mixture plus some kind of baking tray or dish to hold the chocolate biscuit mixture while it sets. I used a 28cm x 18cm x 3cm baking tin, which was just about big enough to hold this amount.
- Line your dish or tray with greaseproof or parchment paper.
- Break each digestive biscuit into 3 or 4 pieces.
- Break all of the chocolate into very small pieces or chop finely.
- Cut the butter into small pieces.
- Place your heatproof bowl over a pot of hot (but not simmering) water and over a very low heat. Add the golden syrup and butter.
- Once the butter has started melting, stir in the chocolate pieces and, stirring constantly, allow the whole mixture to melt together gently.
- Remove from the heat as soon as the chocolate has melted. Add the biscuit pieces and stir to combine.
- Fill your dish or tray with the chocolate biscuit mixture and, if you like, sprinkle with fleur de sel or other salt flakes.
- Allow to set in the fridge for about 2 hours, then cut into slices of whatever size and shape you desire.
- For some reason, I fancy adding some very finely grated or juiced fresh ginger to this.