Position a rack in middle of oven; preheat to 350 degrees Set aside two large baking sheets and four 15-inch-long pieces of parchment.
In a large bowl stir together the flour, brown sugar, cinnamon, ginger, salt, cloves, allspice, and cayenne pepper, if using, until well blended. Thoroughly mash out sugar lumps with the back of the spoon.
In a small bowl whisk together butter, molasses, and coffee until very well blended. Immediately, add butter mixture to flour mixture, stirring vigorously, until evenly incorporated.
Turn dough onto floured surface. Knead with your hands for 30 seconds to make it smoother and more malleable. If dough is too dry or crumbly to roll out, work in a few drops of water until it holds together; if too wet, thoroughly knead in 1 to 2 tablespoons more flour.
Divide dough in half. Roll each portion between two pieces of parchment into a 6x12- inch rectangle. If necessary, cut and patch to make the sides roughly even. (Don't worry about making it perfect.) Peel off top pieces of parchment. Evenly sprinkle each rectangle with about 3 tablespoons coarse sugar and about 1 tablespoon edible glitter, if desired. Lay parchment over dough; gently pressing sugar into dough. Remove top pieces of parchment.
Using a pizza cutter or a large knife, cut each rectangle into 1/4- to 1/3x6-inch strips. It's OK to leave edges uneven. Slide rectangle and parchment onto baking sheets.
Working with one rectangle at a time, bake for 13 to 16 minutes or until just firm when pressed in the center and edges are browned. Immediately slide rectangle and parchment onto a cutting board. Quickly (before rectangle cools and becomes brittlretrace the cuts between strips and cut off uneven edges. (If necessary, return rectangle to the oven; warm until soft enough to work with.) Discard the uneven, overbaked end sections.
Reduce oven to 200 degrees When rectangle is cool enough to handle, use your hands to gently separate strips. Place on a parchment-lined baking sheet. If desired, sprinkle with additional edible glitter. Bake for 10 minutes. Slide strips and parchment onto a wire rack; cool completely.