Preheat the oven to 250°F. Line the bottom of a broiler pan with foil for easy cleanup. Cut the bacon slices in half lengthwise and then crosswire to create 4 long strips. Arrange the crackers on a work surface and wrap a bacon strip around each cracker, overlapping the ends on top. If making Herbed Bacon Crackers, tuck a base of rosemary tips under overlapping ends of bacon. If making Brown Sugar Bacon Crackers, carefully sprinkle 1/8 teaspoon brown sugar on the top side of each cracker, pressing to help it adhere (avoid getting sugar on the cracker or it will burn.) Set a perforated rack on top of the foil-lined broiler pan and arrange the crackers seam-side down 1/2 apart in a single layer and bake for 1 to 1 1/2 hours, until the bacon is at your desired level of crispness. Transfer the crackers to a cooling rack and cool completely before serving.