ready in 4 h. 15 min.
1 Baking sheet, 1 Bowl, 1 Small bowl, 1 Plate, 1 Cutting board, 1 Large knife, 1 Small knife, 1 Tablespoon, 1 Teaspoon, 1 Whisk, 1 Fine grater, 1 Citrus juicer, 1 Salad spinner
Line a loaf tin with cling film.
Melt the butter and syrup in a small pan. Stir and remove from the heat.
Melt the chocolate in a heatproof bowl over a pan of simmering (not boiling) water. Remove from the heat and mix with the buttery syrup.
Stir in the biscuits and raisins and put into the tin. Smooth the top and scatter with the sugar crystals. Chill for at least 4 hours until set.
Cut into slices to serve.