In a medium bowl, toss together dates, cherries, raisins, and currants. Pour 1 cup (240 grams) dark rum and brandy over fruit. Cover and let stand overnight or for up to 3 days. (The longer it stands, the stronger the flavor.)

Preheat oven to 300°F (150°C). Line 2 (8½x4½-inch) loaf pans with parchment paper.

In the bowl of a stand mixer fitted with the paddle attachment, beat butter and brown sugar at medium speed until fluffy, 3 to 4 minutes, stopping to scrape sides of bowl. Beat in molasses until completely incorporated. Add eggs, one at a time, beating well after each addition. Beat in zests, vanilla, and bitters. Add dried fruit and any remaining liquid (about ½ cup [120 grams]).

In a medium bowl, whisk together flour, baking powder, cinnamon, nutmeg, and cloves. With mixer on low speed, gradually add flour mixture to butter mixture, beating just until combined. Divide batter between prepared pans.

Bake for 1 hour. Cover with foil, and bake until a wooden pick inserted in center comes out clean, about 50 minutes more. Let cool in pans for 10 minutes. Remove from pans, and let cool completely on wire racks. Brush loaves with remaining 2 tablespoons (30 grams) dark rum. Top with Rum Glaze. Store in an airtight container for up to 2 weeks.