Prepare the Fruits: Preheat your oven to 325°F (165°C). In a bowl, soak the mixed dried fruits in orange juice and dark rum (if using) for at least 1 hour. Stir occasionally.

Prepare the Cake Batter: In a large mixing bowl, cream the butter and sugar until light and fluffy. Add eggs one at a time, beating well after each addition. Stir in the orange zest and vanilla extract.

Combine Dry Ingredients: In another bowl, sift together the flour, baking powder, cinnamon, nutmeg, and salt.

Mixing: Gradually add the dry ingredients to the wet mixture, mixing until combined. Drain the soaked fruits, reserving a little of the liquid. Toss fruits and nuts with a tablespoon of flour to prevent sinking. Fold fruits and nuts into the batter gently.

Bake the Cake: Pour the batter into a greased and lined loaf pan. Bake for 75-90 minutes, or until a toothpick inserted into the center comes out clean. If the top begins to brown too quickly, cover with foil.

Finish and Cool: Let the cake cool in the pan for 10 minutes, then remove and transfer to a wire rack to cool completely. Brush the reserved soaking liquid over the top for extra flavor and moisture.