Preparation

• In a medium bowl, toss the sprouts with 1 tsp. salt. Set aside.
• Toast the walnuts in a dry medium skillet over medium heat until they just start to darken and smell toasty, about 2 minutes. Sprinkle with the sugar and cayenne, and toss until the sugar coats the nuts. Transfer to a plate to cool.
• Meanwhile, cut the ends off the orange. Stand it on one cut end, and slice off the outer skin in strips, following the natural curve of the fruit from top to bottom. Try to remove all of the bitter white pith without sacrificing too much of the sweet flesh. Working over a bowl to catch the juice and using the membranes as guides, cut the segments free from the membranes, letting each one fall into the bowl as you go. Working over the bowl, squeeze the empty wheel of membranes as well as any skin holding flesh to extract the last drops of juice. Remove the segments from the juice and reserve the juice. Cut the segments into bite-size pieces, and add to the bowl with the Brussels sprouts. Add the walnuts, currants, apple, carrot, and onion, and toss to combine.
• In a small bowl, whisk the orange juice, vinegar, and mustard. Add the oil, and whisk to combine. Add the vinaigrette to the salad, and toss to coat. Add the parsley and toss again. Season to taste with salt, if you like. While you can serve right away, the dish is best refrigerated for up to 1 day. Let come to room temperature, and season to taste with salt before serving.