1. **Soak the Fruit:** At least 24 hours before baking (or up to 3 days), combine the raisins, currants, dates, candied cherries, and citrus peel in a large glass bowl. Pour the rum (or brandy) over the fruit. Stir well, cover, and let it sit at room temperature to plump up, stirring occasionally.

2. **Preheat:** Preheat your oven to 300°F (150°C). Grease two 8×4 inch loaf pans generously. Line the bottom and sides with parchment paper, leaving an overhang to lift the cakes out later.

3. **Cream Butter & Sugar:** In a large bowl or stand mixer, beat the softened butter and dark brown sugar together until light and fluffy (about 3-5 minutes).

4. **Add Wet Ingredients:** Beat in the eggs one at a time, mixing well after each addition. Stir in the molasses and vanilla extract.

5. **Mix Dry Ingredients:** In a separate medium bowl, whisk together the flour, baking powder, salt, cinnamon, nutmeg, allspice, and cloves.

6. **Combine:** Gradually add the flour mixture to the wet ingredients, mixing on low speed just until combined.

7. **Fold:** Gently fold in the soaked fruit mixture (including any liquid left in the bowl) and the chopped nuts until evenly distributed. The batter will be thick and heavy.

8. **Bake:** Divide the batter evenly between the two prepared loaf pans. Smooth the tops with a spatula. Bake for 2.5 to 3 hours. (Check at the 2-hour mark; if the tops are browning too fast, tent loosely with aluminum foil).

9. The cakes are done when a toothpick inserted into the center comes out clean or with just a few moist crumbs.

10. **Cool & Age:** Remove from oven and place pans on a wire rack. While still warm, brush the tops generously with extra rum or brandy.

11. Let cool completely in the pans before removing.

12. **Storage:** Wrap the cooled cakes tightly in plastic wrap, then foil. Store in a cool, dark place. For best flavor, let them age for at least a week, brushing with a little more alcohol every few days.