Place the softened butter, caster sugar, flour, eggs and spices in a bowl and beat well until smooth.
Grease a pudding bowl with butter, then place half of the pudding mixture in the bowl.
Spoon on three tablespoons of mincemeat and then marble it in with a knife skewer or toothpick.
Place the rest of the pudding mixture on top.
Top again with three tablespoons of mincemeat and marble it in again.
Cover the top of the pudding basin with foil.
Get your slow cooker ready. Note: I used my large 5.7 litre Crockpot for this recipe, as I can get a pudding bowl in there.Boil a kettle and pour the boiling water into the slow cooker ceramic pot.
Place the pudding basin, covered with foil, into the water.
Place the lid back on the slow cooker and cook on high for 2 to 2.5 hours, until the pudding has risen in the bowl and the top centre of it looks firm.
Allow to cool, then remove the pudding basin from the slow cooker using oven gloves.
Invert the pudding onto a plate. If there is mincemeat in the base of the pot, spoon it over the top of the pudding. Serve warm with custard, brandy butter or cream.