Grease and flour an 8-inch bundt cake pan.
Cream butter, brown sugar, and vanilla extract until light and fluffy.
Add eggs gradually, mixing until fully incorporated.
Sift in flour and baking powder in batches, mixing gently to avoid overworking.
Stir in the soaked fruits (do not add soaking liquid) until evenly distributed.
Pour batter into prepared pan and smooth the top.
Bake for about 1 hour, or until a skewer inserted into the center comes out clean.
Let cake cool slightly before turning out onto a rack.
While warm, drizzle about 4 tablespoons of the reserved rum over the cake.
Slice and serve with an extra drizzle of the rum liquid, if desired.