In a heatproof bowl, combine golden raisins, sultanas, raisins, and zest. In a small saucepan, heat rum over medium heat (do not boil). Pour hot rum over dried fruit. Cover and let stand for 30 minutes.
Preheat oven to 275°F (140°C). Butter and flour a 6-cup steamed pudding mold.
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. Add eggs, one at a time, beating just until combined after each addition. Beat in molasses.
In a medium bowl, whisk together bread crumbs, flour, cinnamon, salt, baking powder, allspice, and ginger. With mixer on low speed, gradually add bread crumbs mixture to butter mixture, beating just until combined. Add dried fruit mixture and blueberries, beating just until combined. (Batter with be thick.)
Spoon batter into prepared mold, smoothing top with an offset spatula. Cover with lid, and place in a large Dutch oven. Fill Dutch oven with enough water to come three-fourths of the way up pudding basin. (Your Dutch oven should remain uncovered.)
Bake until a wooden pick inserted in center comes out clean, 2 hours and 15 minutes to 2 hours and 45 minutes. (Texture of center will be closer to a pudding consistency than a cake.) Remove lid, and let cool in pan for 20 minutes. Invert onto a wire rack. Serve warm or at room temperature with Maple Butter Sauce.
Notes
You can substitute a 6-cup Bundt pan for the pudding steamer, if desired. In step 5, cover pan with a sheet of parchment paper, followed by a piece of foil. Fasten with twine around lip of pan, and trim overhanging edges. Continue as directed.
Recipe by Bake from Scratch at https://bakefromscratch.com/figgy-duff/