Grease the inside of a 2-pint (1.2 litres) pudding basin with butter and put to one side.
½ tsp soft unsalted butter
Cream together the butter and sugar in a large bowl until light and creamy (or you can use a stand mixer with a paddle).
180 g (6.3 oz) unsalted butter, 180 g (1 cup minus 1 tbsp) caster sugar
Add the eggs, one-at-a-time, whilst stirring (don’t worry if it looks like it’s split – it will come back together).
3 medium eggs
Stir in the milk and vanilla extract, then fold in the flour and baking powder.
1 tbsp milk, 1 tsp vanilla extract, 180 g (1 ½ cups) plain (all-purpose) flour, 2 tsp baking powder
Spoon the jam into the bottom of your greased pudding basin, then carefully spoon the cake mixture on top.
7 tbsp raspberry jam
Cover the top of the pudding basin with a layer of baking parchment. Fold a pleat across the centre, so there’s a little room for the pudding to expand. Secure the pleated parchment with a piece of string tied tightly under the rim of the pudding basin, and cut off any excess parchment paper.
Place the basin, parchment-side-up into the slow cooker and add boiling water, from the kettle, into the slow cooker bowl, around the sides of the basin, so it comes about three-quarters of the way up the pudding basin.
Place the lid on the slow cooker and cook on high for 2 ½ hours.
Once cooked, carefully remove from the slow cooker and remove the string and parchment (be careful, as steam will escape as the paper is removed).
Place an upside-down plate on top of the pudding basin and carefully invert, turning the jam sponge out onto the plate.
Serve topped with cream, custard, or ice cream.
Video
Notes
Nutritional information is approximate per serving.