1. Place a vegetable steamer or other low rack in the bottom of a 5-quart electric slow cooker. Pour in 4 cups hot tap water and turn on the low heat setting.
2. In the large bowl of an electric mixer, combine the cake mix, eggs, melted butter, milk, cardamom, cinnamon, coriander, allspice, ginger, mace, and nutmeg. Beat on low speed 20 to 30 seconds to combine the ingredients, then beat on medium speed 2 minutes. Fold in the dried cranberries, dark and golden raisins, candied lemon and orange peels, citron, and pecans.
3. Sprinkle a 2 1/2-quart souffle dish that fits in the 5-quart slow cooker with the sugar. Turn the cake batter into the souffle dish, spreading the top even. Place a buttered round of waxed paper on the top and then wrap the dish completely in a double thickness of aluminum foil. Tie with kitchen string to resemble a package for ease in lowering into the pot and removing. Place on the rack in the slow cooker.
4. Cover and cook on the low heat setting 6 hours. Turn off the heat and let cool, covered, in the slow cooker 2 hours. To serve, cut into wedges and drizzle glaze on top.