Black Cake - Caribbean Christmas Cake

1/2 lb butter, softened
1 cup sugar
2 tablespoons browning sauce (helps to darken the cake, especially if you don't use dark rum in the cake) (optional)
1 teaspoon vanilla
1 1/2 cups all-purpose flour
1 teaspoon baking powder
1 teaspoon cinnamon
1/2 teaspoon allspice
1/2 teaspoon salt
4 large eggs
1 cup dark rum (brandy can be substituted, as can red wine)
1/4 lb mixed peel
1/4 lb cherries
1/4 lb mixed nuts, of your choice (unsalted) or nuts, of your choice
1/2 lb prunes, chopped
1 lb raisins
1 freshly grated lime, zest of or lemon, zest of

Preheat oven to 325F; spray a nine-inch cake pan with nonstick cooking spray and set aside.
In a mixing bowl, beat together the butter, sugar, vanilla and browning until soft and creamy.
In a separate bowl, sift together the dry ingredients.
In a third bowl, beat the eggs with the rum.
Add egg mixture to butter mixture and thoroughly combine, then stir in zest, fruit and nuts.
Fold in flour mixture; do not overbeat.
Put batter into prepared pan and bake in preheated oven for approximately 90 minutes, or until cake tests done; may need longer.
Remove cake from pan when cool.