Heat oven to 200C/180C fan/gas 6. Mix the muffins with the sultanas. Divide between 4 buttered ramekins or one baking dish. Cover with foil and bake for 8 mins until just warmed through.
Meanwhile, place the sugar, butter and cream in a small pan and gently heat together, stirring until the sugar dissolves. Pour the sauce over the muffin mixture and serve warm with ice cream.