Place sultanas and sherry in a small bowl. Stand until required.
Preheat oven to 180C/160C fan-forced. Grease eight ¾ cup (180ml) capacity pudding moulds or ovenproof dishes. Line bases with baking paper.
Stir brown sugar, butter, molasses, ginger and mixed spice in a saucepan over low heat until the sugar dissolves and mixture is smooth and glossy. Stir in sultana mixture. Cool for 5 minutes.
Transfer butter mixture to a large bowl. Whisk in milk and eggs until combined. Stir in flour and bicarbonate of soda until combined.
Spoon mixture evenly among prepared moulds. Place moulds on a baking tray. Cover with baking paper, then foil. Bake for about 35 minutes or until a skewer inserted into the centres comes out clean. Set aside in moulds for 5 minutes to cool before turning onto plates.
Meanwhile, heat caster sugar in a non-stick frying pan over low heat, shaking the pan, for 10 minutes or until the sugar dissolves and is dark golden. Carefully and slowly add cream. Stir over low heat for 10 minutes or until the toffee dissolves and sauce thickens. Stir in salt. Transfer to a heatproof jug. Set aside until required.
Serve warm puddings drizzled with warm caramel sauce.
If you want to omit the alcohol, replace it with orange juice or extra milk.