unsalted butter 60g,
melted plus more for the dish
Heat the oven to 190C/fan 170C/gas 5. Mix the brown sugar, cornflour, mixed spice, star anise and vanilla. Toss with the berries, and tip into 20cm x 30cm buttered ovenproof dish.
Sieve the flour into a bowl, add the sugar, spices, a pinch of salt, and beat in the melted butter, and enough buttermilk to make a thick, smooth mix that just falls off the spoon.
Spoon large dollops of the dough over the berries, don’t worry if it doesn’t cover it completely. Bake for 40-45 minutes until the topping is golden and crisp.
Leave to sit for 20 minutes, then serve warm with custard or cream, or allow to cool completely.
Wrap the slump in clingfilm and freeze until solid. To reheat, remove the clingfilm, cover in foil and heat the oven to 160/fan 140C/gas 3. Reheat the slump for 50 minutes – 1 hour until bubbling, and the middle is piping hot when poked with a metal skewer. Serve with custard or cream.