Combine the rum and raisins in a small bowl and leave for 1 hr for the raisins to plump up. Alternatively, microwave on high for 45 seconds, then set aside to cool. Heat the oven to 180C/160C fan/gas 4 and butter a deep baking dish (ours was 27 x 22cm and 5cm deep).

Pour the melted butter and milk into a bowl or jug and beat in the eggs. Sift the flour and baking powder into a large bowl, then mix in the caster sugar. Pour the wet ingredients into the dry along with the soaked raisins and stir everything together until well combined. Pour the batter into the prepared dish.

For the sauce, whisk the sugar and rum together in a heatproof jug or bowl, then pour in 300ml boiling water. Pour the sauce into the dish over the batter (don’t worry if it looks messy at this stage, the sauce will sink to the bottom as it bakes). Bake for 40-45 mins until the top is golden. Serve warm with custard or cream, if you like.