Step 1

Lightly grease the inside of a 23cm/9in square baking tin. Line the base and sides of the tin with baking paper.

Step 2

Put about 2.5cm/1in of water into a medium saucepan. Find a heatproof bowl that will fit the top of the pan snugly. Make sure the base of the bowl doesn’t touch the water.

Step 3

Put the pan on the stove and bring the water to the boil. Reduce the heat to low and put the chocolate, golden syrup and butter into the bowl. Stir occasionally, making sure to agitate the chocolate, as this will encourage the mixture to come together. As soon as the mixture is smooth and liquid and runny, take off the heat and allow to cool for about 10 minutes.

Step 4

Add the salt and cinnamon and mix through.

Step 5

Crush the biscuits very roughly by putting them into a freezer bag and crushing them with a rolling pin. Empty the contents of the bag into the chocolate mixture. Give it a stir. Add the marshmallows, apples and raisins and stir until everything is well coated.

Step 6

Pour the mixture into the prepared tin and use the back of a spoon to flatten it and press it into the corners.

Step 7

Put the tin into the fridge for at least 1 hour, or until set.

Step 8

Take out of the tin and unwrap. Dust with the icing sugar and slice into 18 bars.