Grease an 8-inch by 4-inch loaf pan with butter and set it aside.(You can also use a 6-inch by 4-inch round cake pan or an 8-inch by 2-inch cake pan.) Preheat your oven to 300º F.
Mix the rum and fruit in a small saucepan and warm it on the stove. Once warm, set the saucepan aside for 15 minutes or so to let the fruit soften.
Sift together the flour, baking powder, salt, and spices in a bowl.
In a separate bowl, cream the butter, brown sugar, molasses, and orange zest on medium speed. Add the eggs, one at a time, and mix thoroughly. Then add the flour mixture slowly, mixing on low speed. Avoid over mixing the dough — just mix until everything is moistened.
Once mixed, fold in the fruit and nuts, then pour into the pan. You can top the loaf with pecan halves if you'd like. Bake for 1 ½ to 2 hours. A skewer inserted in the middle of the fruitcake should come out clean when it’s done. Make sure to let the fruitcake cool for two or three hours before you serve it.