1. Preheat the oven to 190C/375F.
2. Cut the spice bread into thin slices. Place the slices on a baking sheet. Bake for 5 minutes. Remove from the oven and let cool. Then, blend the spice bread into a powder using a blender.
3. In a saucepan, heat the mandarin oranges in their syrup until the juice is reduced by half. Remove from heat and let the oranges cool.
4. Drain the mandarin oranges and add the spice bread powder.
5. Cut each brick sheet in half. Fold the round edge over the straight edge to form a rectangle.
6. Place the mandarin filling at one end; fold several times, from one edge to the other, until the other end, maintaining a triangular shape. Brush with melted butter.
7. Place on a baking sheet lined with parchment paper.
8. Bake for 10 minutes.
9. Remove from the oven and serve.