1.Firstly make the salted caramel sauce. Place the caster sugar in a large, heavy-based, stainless-steel (so you can see the colour) saucepan with 3 tablespoons of water and bring to the boil over a medium heat, stirring occasionally. Reduce the heat and simmer, without stirring, for 6-8 minutes until amber in colour. Remove from the heat and add the brown sugar, butter and cream. The mixture will bubble, spit and become lumpy but just stir vigorously until it dies down. Return to the heat, turn it up and allow to bubble for a further 2 minutes, continuing to stir until it forms a smooth thick sauce. Remove from the heat and leave to cool to room temperature. Once cool, this will keep for 2-3 days in an airtight container in the fridge.

2. To prepare the chocolate layer, bring the cream gently to the boil in a medium pan on a medium heat. Meanwhile, snap the chocolate into a large jug. Remove the cream from the heat once it reaches the boil and pour over the chocolate. Stir until melted to a smooth, rich sauce, then leave to cool to body temperature. Meanwhile, oil the loaf tin and line with parchment paper.

3. Stir the nuts through the salted caramel sauce and then pour into the base of the tin, spreading it evenly with the back of a spoon. Pour the cooled chocolate mixture on top, cover with cling film and refrigerate for at least 4 hours or overnight, until set firm. This can be made up to 24 hours in advance and left in the fridge.

4. Just before you want to serve, lay a long serving board upside down over the tin and turn both over together, allowing the terrine to drop out. Remove the tin and peel off the paper to reveal the turtleback. Leave to come to room temperature for 15-20 minutes before serving. Dipping your knife in boiling water and wiping dry between every slice, cut into 12 slices, serving 2 per person.

For an added twist . . .

– The chocolate layer can be flavoured with any of the following: finely grated zest of 1 orange or lime; a dash of brandy, Baileys or Amaretto; 2 tsp instant coffee; 125g fresh raspberries; a finely chopped red chilli; 1 tsp ground cinnamon.

– Serve the chocolate layer alone by pouring into small espresso cups or pretty glasses. Set and serve with a crisp biscuit.

This recipe is from my book No-Bake Baking, available worldwide in all good bookstores or on Amazon.

Photo © Donal Skehan