Cream together the butter and the sugar until it is light and fluffy.
Beat in the eggs bit by bit. Ensure each addition is mixed well.
Fold in the flour.
Rinse the cherries and dry them on kitchen towel.
Toss the cherries in the extra flour, keeping a few aside to put on the top.
Add the dusted cherries and the vanilla bean paste or extract to the mixture and stir in gently.
Line your slow cooker pot. You can either use baking paper or a large cake tin case. I use two layers of baking paper to prevent burning.
Place the cake mixture in the lined pot, and use a spoon to smooth the top.
Place a tea towel under the lid of your slow cooker, fold up the edges of the tea towel so they aren't hanging down, then put the lid on the slow cooker.
Cook on high for 2 hours, or until a skewer comes out clean.
As soon as the pot has cooled a little, use the lining to pull the cake out, and leave it to cool on a rack.
If you want icing, mix the icing sugar with a few drops of water and drizzle over the cake once completely cool.