1) Preheat the oven to 425°F. Line two baking sheets with parchment paper and set aside.
2) In a large mixing bowl, whisk together the self-rising flour,allspice and dried fruits. Dice the cold butter into small cubes and work into the flour mixture until it resembles chunky granola, with some larger bits of butter still remaining.
3) Mix in the sweet potato and milk until you have a moist, cohesive dough. If the dough is on the drier side, add more milk until it is moist and slightly sticky.
4) Turn the dough out onto a very lightly floured surface and pat out to a 10" x 14" rectangle. Transfer the rectangle to one of your parchment-lined baking sheets and brush the dough with half of the softened butter.
5) Place the butter-topped dough into the freezer for 10 minutes. Remove and fold the dough in thirds, like a business letter. The cold layer of butter will help give flakiness to the final biscuits.
6) Repeat steps 4 and 5 once more. After you remove the dough from the freeze and fold, roll or pat the dough out to a rectangle once more and cut the dough into 8 bars, approximately 2" x 4" . You can also cut traditional round or square biscuits if desired.
7) Place the cut biscuits onto the two baking sheets and bake in the preheated oven for 20 to 25 minutes, or until the edges begin to brown slightly.
8) While the biscuits cool slightly, mix the glaze ingredients to a spreadable consistency. Brush over the warm biscuits and serve immediately. For a less sticky treat, you can cool the biscuits to room temperature before serving.
9) Yield: 8 biscuit bars