In a saucepan, combine the fruit, 180 ml (3/4 cup) orange juice and 125 ml (1/2 cup) rum and bring to a boil. Lower the heat and simmer for 2 minutes. Remove from the heat and let stand for 10 minutes. Strain, reserving the cooking juices and the fruit. Let cool.
With the rack in the middle position, preheat the oven to 150°C (300°F). Butter and flour the sides of a 33 x 23 cm (13 x 9-inch) Pyrex baking dish and line the bottom with parchment paper.
In a bowl, combine the flour and baking powder. Set aside.
In a separate bowl, cream the butter with the brown sugar and molasses. Add the eggs one at a time, beating until the mixture is smooth.
With the mixer on low speed, add the dry ingredients, alternating with the reserved cooking juices and remaining orange juice. Using a wooden spoon, stir in the fruit.
Spread the batter evenly in the baking dish and bake until a toothpick inserted into the centre of the cake comes out clean, 50 to 55 minutes. Let stand for 5 minutes. Run a knife around the inside edge of the pan, then unmould the cake by inverting it onto a cooling rack. Pull away the parchment paper and brush the cake with the remaining rum. Cool to room temperature. Even the sides of the cake by trimming them with a knife. Set aside.
Sprinkle icing sugar on a work surface and roll 350 g of marzipan into a 33 x 23-cm (13 x 9-inch) sheet. Cover the top of the cake with the sheet and press into place. Using scissors, trim the sheet so it is even with the edges of the cake. Cut the cake into 24 squares.
In a bowl, combine the marzipan trimmings, the remaining marzipan and a few drops of food colouring. Knead together until smooth. Roll out the paste. With a small Christmas cookie cutter or the tip of a knife, cut out seasonally appropriate shapes (holly leaves, stars, bells, etc.) and decorate the cakes with them.
Wrap the cakes individually with the plastic wrap and transfer to the gift boxes.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.