Combine first 5 ingredients in extra large bowl; dd rum and toss until coated
Cover for 2 to 3 days in a cool place
Line two 9 x 5-inch (2 litre) loaf pans with 3 layers of parchment paper
Whisk together flour, baking powder and salt in medium bowl; set aside
Cream butter and sugar together until light, then eat in eggs, one at a time; stir in orange rind and almond extract
Add 1/3 of flour mixture to egg mixture stirring to combine; add 1/4 cup Grand Marnier until combined
Repeat with another 1/3 flour mixture, 1/4 cup Grand Marnier and remaining flour mixture, stirring each just until combined
Stir almonds into fruit mixture; gently fold batter into dried fruit mixture
Divide and press into prepared pans
Preheat oven to 250°F or 120°C
Set a shallow baking dish filled half way with boiling water on lower oven rack; place loaf pans on centre rack
Bake for about 2 1/2 hours, or until wooden pick inserted in centre comes out clean. (You may need to cover the cakes with foil for the last half hour if beginning to crack or browning too quickly.)
Remove pans to wire racks and brush with remaining 1/4 cup of Grand Marnier; cool completely
Remove from pans; discard parchment paper
Wrap cakes in cheesecloth that has been drizzled with a small amount of Grand Marnier or brandy
Wrap in foil, seal in freezer bags and store in cool place for up to 1 month or freeze for up to 1 year