Chocolate Truffle Cake
Because when you make a giant chocolate truffle, the best thing to decorate it with is more chocolate truffles, naturally. If you're not a big chocolate fan, sorry but this one's probably not for you. Sorry to anyone who has given up chocolate for lent, and sorry if you are no longer doing that as a result of this post.
Utensils: 20cm / 9in loose-bottomed cake tin, non-stick baking paper, plastic food bag and rolling pin or food processor, hand whisk or wooden spoon, palette knife, non-stick silicone baking mat (not essential), heart (or other shaped) cookie cutter (not essential), toothpicks and polystyrene foam (not essential), sieve, fancy presentation plate for you to display your masterpiece on.
Top Tip #1: This recipe goes down a treat at big events such as Christmas, birthdays and dinner parties. The cake is very rich so a small piece is usually more than enough for most people, apart from serious chocolate fiends who will probably want to take a piece home and might keep snacking on your chocolate truffles when they think no one else is looking. This cake should easily serve 12-15 people and for those who might find it a bit rich on its own, make sure you have some single or double cream or vanilla ice cream on hand to serve it with.
Top Tip #2: This recipe requires quite a lot of fridge / freezer space, so make sure you have some space cleared in both before you start so that you don't end up having to rearrange your fridge and freezer halfway through when you're probably already covered in chocolate.
250g chocolate digestive biscuits (ensure gluten-free if desired)
100g unsalted butter, melted
1 tablespoon cocoa powder
Chocolate Truffle Filling
400g dark chocolate, chopped into pieces
60ml rum (optional)
60ml golden syrup
1 teaspoon vanilla extract
500ml double cream
Decorative Chocolate Truffles
200g dark chocolate, chopped into pieces
25g unsalted butter, softened and cut into small cubes
1/2 teaspoon vanilla extract
100ml double cream
40g dark soft brown sugar
Pinch of salt
200g milk chocolate, chopped into pieces
Cocoa powder, to dust
1. Make the biscuit base: Grease the base and sides and line the base of a 20cm / 8in loose-bottomed cake tin with non-stick baking paper. Put the chocolate digestive biscuits in a plastic food bag and crush to crumbs using a rolling pin, or use a food processor to whizz the biscuits into crumbs.
2. Transfer the crushed biscuits to a mixing bowl and add the melted butter and cocoa powder. Mix thoroughly until the crumbs are completely coated. Tip the biscuit mixture into the cake tin and press firmly and evenly to the bottom of the tin using the back of a spoon or the palm of your hand. Put the cake tin in the fridge to allow the base to set firmly for at least half an hour.
3. Make the chocolate truffle filling: Chop the dark chocolate into small pieces and place in a large heatproof bowl. Add the rum (if using), golden syrup and vanilla extract to the bowl. Place the double cream in a saucepan and heat slowly until the cream reaches boiling point. Pour the hot cream over the chocolate and leave for a minute to allow the chocolate to melt. Then, beat with a hand whisk or wooden spoon until smooth.
4. Remove the cake tin from the fridge and pour the chocolate truffle mixture over the top of the biscuit base. Cover the cake tin with clingfilm and place back in the fridge ideally overnight or for at least several hours to allow the chocolate truffle mixture to set.
5. Make the decorative chocolate truffles: Place 110g of the chopped dark chocolate and into a heatproof bowl along with the softened butter and vanilla extract. Place the double cream and dark soft brown sugar into a saucepan and heat slowly until the cream reaches boiling point. Pour the hot cream and sugar mixture over the chocolate, butter and vanilla and leave for a minute to allow the chocolate to melt. Then, beat with a hand whisk or wooden spoon until smooth. Add a pinch of salt and mix until combined.
6. If you plan to make conventional chocolate truffles by rolling the mixture into little balls, allow the mixture to cool before covering with clingfilm and placing in the fridge to set (this should take around 2 hours). If you want to make heart (or other shaped) chocolate truffles using a cookie cutter like I did, sprinkle a fine layer of cocoa powder over a non-stick silicone baking mat (which you can find on Amazon HERE* if you want to buy one yourself) or a large piece of non-stick baking paper, and then use a palette knife to spread the chocolate truffle mixture over the baking mat / paper in a thick layer. Pop in the fridge to set (this should take around 2 hours) or the freezer if you don't have 2 hours spare.
7. If you are rolling your truffles into balls, use a teaspoon to scoop out small amounts of truffle mixture and then roll by hand into balls before popping back in the fridge to chill. Another less messy method you could use is to roll all of the truffle mixture into a long, thin log wrapped in clingfilm, pop in the fridge to set again and then slice into short cylinders. If using a cookie cutter, cut away and then put your cut truffles back into the fridge to set again. For the large centre truffle in the middle of the cake as shown in the photos above, I used an ice cream scoop to make this shape.
8. While your truffles are setting in the fridge again, melt the milk chocolate carefully in short bursts in the microwave or in a heatproof bowl over a pan of simmering water. Once melted, allow to cool a little (if you want to temper the chocolate and you have a thermometer, the chocolate needs to be at 31°C when you dip) before dipping the truffles into the chocolate. For dipping, you might find it useful to transfer your melted chocolate into a small but deep bowl so that the truffles can easily be pushed underneath the surface of the chocolate to be coated.
9. There are a couple of different methods you can use to dip your chocolate truffles:
If your truffles are round or short cylinders, you could insert toothpicks into the truffles, dip them into the milk chocolate and then stick the toothpicks into a piece of polystyrene foam to allow the excess chocolate to run off. Place back in the fridge or freezer to set.
If your truffles are heart (or other) shaped, then toothpicks don't work so well. Instead you could slide the edge of a fork under the truffle, lift it up gently and drop it into the melted milk chocolate. Push the truffle under the surface of the milk chocolate and then lift out with the fork, tapping the fork against the side of the bowl to remove any excess chocolate. Place the dipped truffle onto a baking sheet lined with non-stick baking paper and slide the fork out from underneath. If the truffle sticks to the fork, use a small knife or palette knife to push the truffle off the fork onto the baking sheet. Place back in the fridge or freezer to set.
I decided to only dip half of my chocolate truffles in the milk chocolate and leave the other half 'naked' so there would be a little more colour variation on the cake. Do what you want with yours!
10. To assemble the chocolate truffle cake, remove the cake tin from the fridge and slide a knife around the edge of the cake before removing the base from the tin (e.g. by pushing the base up through the tin or by releasing the catch on the side of the tin). To remove the base of the tin from the cake, slide a palette knife between the tin's base and the baking paper underneath the biscuit base. Life the palette knife up to allow you to get a hand underneath to remove the baking paper and to transfer the cake onto your presentation plate.
11. For the finishing touches use a sieve to dust a small amount of cocoa powder on the top of the cake and the edges of the presentation plate. Then arrange your chocolate truffles as you fancy on top of the cake. Melt the remaining 90g of dark chocolate and use a fork to drizzle this over the cake for the ultimate chocolate overload.
Serving suggestions: Single cream, double cream, brandy cream (if serving at Christmas) and vanilla ice cream all work a treat!
Storage: Store in an airtight container or wrapped in clingfilm in the fridge for up to 5 days (if it lasts that long).