1. Place the mustard and sugar in a nonreactive mixing bowl and whisk to mix. Gradually whisk in the vinegar, oil, and hot sauce. Season with salt and pepper to taste; the dressing should be highly seasoned. Set the dressing aside. 2. Finely chop the cabbage in a food processor fitted with a metal chopping blade, running the machine in short bursts; this is a chopped, not a shredded, slaw. Work in several batches so as not to overcrowd the processor bowl (overprocessing will reduce the cabbage to mush). Finely grate the carrot by hand or using the shredding disk of the food processor. 3. Add the cabbage and carrot to the dressing and toss to mix. Taste for seasoning, adding more salt and/or vinegar as necessary. The slaw tastes best served within a few hours of being made but can be refrigerated, covered, for a day or two. Taste for seasoning before serving, adding more salt and/or vinegar as necessary, and toss to remix.