340g self-raising flour
340g finely grated butter (about 115g/4oz)
340g fresh brown breadcrumbs (from around 4 thick slices of bread)
340g light muscovado sugar
340g mixed nuts, chopped plus extra to decorate
1 tsp ground cinnamon
1 tsp ground mixed spice
1 large egg
Butter, for greasing
For the butterscotch sauce
100g light muscovado sugar
200ml double cream
1 tsp vanilla extract
1. For the pudding, empty the first six cups and the nuts, if using, into a mixing bowl with the spices, then stir in the milk and egg. Once well combined, tip into a buttered 1.5 litre pudding bowl.
2. Cover with a double layer of buttered foil, making a pleat in the centre to allow the pudding to rise. Tie the foil securely with string, then place in a steamer or large pan containing enough gently simmering water to come halfway up the sides of the bowl. Steam, covered with a lid, for 21⁄2 hours. Check the water level during cooking, topping up if necessary. If you are preparing this pudding ahead, remove the foil, let it cool slightly, then wrap in cling film and then fresh foil. If you are serving it immediately, unwrap and invert onto a deep plate.
3. For the sauce, put everything in a pan and bring slowly to the boil, stirring. Allow to bubble away for 2-3 minutes, still stirring, until the sugar has dissolved and the sauce is pale caramel in colour and slightly thickened. Remove from the heat. Pour the sauce over the pudding and decorate with the whole mixed nuts.