1. Line a 30cm x 20cm tin (or thereabouts) with baking paper.
2. Place the raisins or sultanas in a small bowl and pour over the sherry. Cover and leave to soften for 30 minutes.
3. In a large saucepan melt the butter, condensed milk and cocoa powder.
4. Crush the vanilla wine biscuits in a food processor, leaving some pieces of biscuit a little larger. Stir crushed biscuits and the softened raisins with any remaining sherry through the butter mixture. When well combined, spoon into the prepared tin and spread evenly. Cover and refrigerate until firm.
5. To make the icing, place the icing sugar, cocoa powder and butter in a bowl. Drizzle in enough boiling water to thin to a spreadable consistency. 
6. Spread icing over the set chocolate fudge slice in a thin layer and leave until the icing is set. Cover and return to the fridge.
7. Chocolate fudge slice is best left in the fridge overnight before eating. (Actually, it improves with age so I find making plenty is a good idea.) Cut into small pieces as you require or cut up and place in an airtight container.

See more of Kathy's sweet treats

• Almond fingers
• Victoria sponge