Preheat oven to 160C. Place the prunes, raisins, boiling water, rum and baking soda in a bowl and set aside for 10 minutes. Then process the prune mixture in a blender until smooth and set aside.
Place flour and sugar in a large bowl and mix to combine with a hand whisk.
Add in melted butter and vanilla extract and mix well. Then add eggs, mix well again and lastly add the prune mixture into it. Mix well with handwhisk till combined.
Spoon mixture into a well-greased with cooking spray - (9 inch) bundt pan and bake for 160 degree C for 35-40 minutes or until cooked when tested with a skewer.
Allow to cool in the pan for 15 minutes, before turning onto a wire rack to cool completely.
To make the caramel sauce, place the butter, sugar, golden syrup, whipping cream and rum in a sauce pan over medium heat and stir until sugar is dissolved.
Bring to the boil and cook for 12 - 15 minutes or until thickened. Allow sauce to cool for 10 minutes before pouring over the cake to serve.
Recipe by Anncoo Journal at https://www.anncoojournal.com/rum-and-prune-cake-with-caramel-sauce/