Mix all the fruit in a large bowl. Add in the orange or satsuma zest and juice, then the tea. Mix it well, then cover the bowl with clingfilm and leave it to soak overnight.
When you are ready to make the cake the next day, cream together the sugar and butter in a large bowl.
Next, add in the three eggs and beat well.
Fold in the flour, spices and vanilla bean paste, and combine well.
Mix in the soaked fruit and any remaining liquid.
Grease and line a 20 cm round silicone pan on the base and sides with a double layer of baking paper.
Place an upturned saucer or small tin on the base of your slow cooker. You will need to use a large slow cooker (mine is 5.7 litres) that your pan fits into. Placing the pan on a saucer will stop the base of the cake burning during the long cooking time needed for this dense cake.
Spoon the cake mixture into your prepared silicone pan, and smooth it down on top.
Pour some hot (not boiling or your pot might crack) water into your slow cooker pot, around the saucer. I used a couple of inches and topped it up once during cooking.
Now place your silicone pan on top of the upturned saucer.
Place a clean tea towel under your slow cooker's lid, to catch condensation during cooking and stop it making the top of the cake soggy.
Switch the slow cooker on high and cook for 3-4 hours, until the top looks firm and a cake tester or skewer comes out clean from the centre.
Remove from the slow cooker and allow it to cool.