Place the fruit and nuts into a pot, add the rum and enough water to cover the fruit and nut mixture.
Boil up briefly and simmer on a very low heat for 45 minutes.
Strain and keep the liquid so you can use the fruity water for the dough.
Prepare the main dough using the flours, yeast, salt, ground spices and the fruity water. Add more water to make up the required quantity if you don't have enough sieved water.
Knead for about 10 minutes, then add the fruit and nut mix until evenly distributed.
Place the main dough into a large bowl, cover and leave to rest for about 1 1/2 hours at room temperature.
In the meantime, prepare the dough for the outer layer (see ingredients for the dough shell) by combining the flours, yeast, salt and water.
Knead for 10 minutes, then place the dough into a small bowl and leave to rest for about 1 1/2 hours at room temperature.
Go back to the main dough once risen, punch down and divide the dough into two equal parts.
10. Shape each part into a flattish oval loaf and place them on two baking trays lined with baking paper.
11. Take the dough you prepared for the outer layer of the loaf. This is going to be the outside hull which is going to be used to avoid the fruit from burning. Divide into two equal parts and, with a rolling pin, roll out the dough to about 3 mm in thickness. Roll out with a view to wrap the two fruit loaves you prepared, then gently cover the loaves. The dough shell doesn't need to cover the fruit dough at the bottom, simply tuck in the outer layer so it doesn't peel off during the bake. Finally, make sure the outer and inner dough parts are well connected.
12. Use a fork to make a decorative pattern on each of the loaves.
13. Rest for 30 minutes and preheat the oven to 190°C in the meantime.
14. Brush the loaves with water and bake at 190°C for 10 minutes. Turn down the heat to 170°C and bake for a further 25 minutes. Cover the loaves with tin foil in case they brown too quickly.
15. Just before you take the loaves out of the oven, prepare the mixture for brushing by bringing the water, potato starch and sugar to the boil. Watch carefully and take it off the heat as soon as it has gelatinised.
16. Brush on the mixture when the loaf is still hot.
17. Cool on a wire rack.
18. Serve with butter, it's delicious!