In a saucepan, bring the rum to a boil. Turn off the heat and add raisins and prunes into it. Cover and wait until the fruit has absorbed most of the liquid. If it doesn't happen, turn on the heat and simmer, until most of the liquid is absorbed. Allow to cool and puree dried fruit in a blender. Set aside.
Preheat oven to 350°F (175°C). Half-fill a baking pan with water and place it on the oven's bottom shelf to create steam. Spray a 9-inch cake pan with cooking spray, line with parchment paper, and spray again. Dust it with flour, tapping out excess.
In a bowl, sift together the flour, baking powder, salt, cinnamon, and nutmeg. Set aside.
In a stand mixer with a paddle attachment, cream the butter and brown sugar until light and fluffy. Add the eggs, one at a time, until they are incorporated. Add the vanilla extract, molasses and the pureed dried fruit and mix just until they are combined. On a low speed, add the sifted flour mixture, in batches. Finish by incorporating the final batch of the flour mixture with a rubber spatula.
Pour the batter into the prepared cake pan and bake for about 45-60 minutes, or until a toothpick comes out clean.
When ready, transfer to a cooling rack, wait for 5 minutes, and flip the cake upside down. Remove the pan and the paper and sprinkle with the reserved ¼ cup of rum. Allow to cool and flip the cake back to it's upright position. Dust with powdered sugar. You can garnish the cake with cherries or strawberries. Enjoy!