Sweet potatoes add nutrition, flavor, and moisture to these bars, which are handy for an on-the-go breakfast or power snack. We add in dried fruit and ginger for even more chew and natural sweetness.
Lightly grease two baking sheets, or line with parchment.
For the bars: In the bowl of a stand mixer fitted with a paddle, blend together the flour and allspice. Dice the cold butter into 1/2" cubes and work into the flour mixture at low speed until it looks crumbly, with some larger bits of butter remaining. Stir in the dried cranberries and crystallized ginger.
Mix in the sweet potato and milk at low speed until you have a moist, cohesive dough. If needed, add another teaspoon or two of milk to bring the dough together.
Turn the dough out onto a lightly floured sheet of parchment and pat out to a 10" x 14" rectangle. Brush the dough with 4 tablespoons of the softened butter and fold it in thirds, like a business letter. Place the dough in the freezer for 10 minutes or refrigerator for 15.
Remove the dough, roll out once more, and spread with the remaining 4 tablespoons of butter. Fold in thirds once more, and chill for 10 minutes.
Preheat the oven to 425°F.
Pat or roll the dough to a 9" x 14" rectangle. Trim 1/4" of dough from the long edges and cut into sixteen 2" x 4" bars. Pile the scraps together and bake as your tasting sample. Transfer the bars to the prepared baking sheet.
Bake for 20 to 25 minutes, or until the edges are lightly browned. Remove from the oven and let cool on a rack.
For the glaze: Mix the glaze ingredients together until smooth and brush or drizzle over the bars while still warm.
Serve warm or let cool completely to set the glaze before eating. Store, covered, at room temperature for 2 days or frozen for up to a month.
