Preheat the oven at 170C for 15 min. Line a 7- or 8-inch cake tin with parchment paper.

In a pan, add the sugar and heat it till it melts and turns a golden brown color. The darker the color, the more bitter the caramel. As it starts bubbling and frothing up, add the hot water to stop further cooking of the caramel and take it off heat.

In a bowl, whisk together the butter and sugar till creamy and smooth. Add the buttermilk to this and whisk well. To this, fold in the flour, baking powder, cake spice mix, and salt. Once all the dry ingredients are well incorporated in the batter, add the vanilla essence and cooled caramel and mix well. To this, add the soaked fruits and mix.

Pour the batter into the lined cake tin. Bake it at 170C for 70-80 min till the top looks done and a skewer inserted comes out clean. As soon as the cake comes out of the oven, sprinkle rum on top and let the cake cool down. Store the cake cling wrapped and keep feeding rum every couple of days or cover it in a muslin cloth soaked in rum and store it.