Step 1

Line a 23 x 23cm (9 x 9 inch) tin with baking paper

Step 2

Melt the chocolate in a glass bowl over a pan of just-boiled water. Do not allow any water to touch the chocolate! (See Note 1.)

Step 3

Remove the bowl from the saucepan when the chocolate is fully melted.

Step 4

Place the biscuits in a plastic sandwich bag (or similar). Bash into small chunks using a rolling pin and add to the melted chocolate. (You may need to transfer everything to a bigger bowl.)

Step 5

Add the mini marshmallows to the bowl and stir everything together thoroughly.

Step 6

Transfer the mixture to the lined tin. Spread the mixture out and then press down using the back of a large spoon or similar (I actually use a potato masher to press the mixture flat, which works really well!)

Step 7

Chill for 1 hour in the fridge, then remove and cut into 16 squares with a sharp knife.