Sweet Potato Salad

4 medium sweet potatoes (about 2 pounds), peeled and cut into uniform large pieces
1/2 red bell pepper, seeded and diced small
1/2 green bell pepper, seeded and diced small
1/2 large red onion, diced small
4 tablespoons finely chopped parsley
For the dressing
3 tablespoons Dijon mustard
3 tablespoons ketchup
1 teaspoon minced garlic
3/4 cup olive oil
4 tablespoons cider vinegar
1 tablespoon Worcestershire sauce
2 tablespoons lime juice (about 1 lime)
Salt and freshly cracked black pepper to taste

Plug up your sink and fill it with about 5 quarts of cold water and a couple of trays of ice cubes. In 3 quarts of boiling salted water, cook the pieces of sweet potato until just done, 10 to 12 minutes. Be careful not to overcook. You should be able to pierce them with a fork, but you should still feel some resistance, and the pieces should not fall apart. Remove the pieces of sweet potato from the heat, drain, and immediately plunge them into the ice-water bath. After about 30 seconds, drain them again, and put them into a large stainless steel bowl. Add the diced pepper, onion, and parsley. Make the dressing: Place the mustard, ketchup, and garlic in a medium-sized bowl. Whisking constantly, add the olive oil in a slow, steady stream. Add the vinegar, Worcestershire sauce, and lime juice, and mix well. Season with salt and pepper to taste.
Pour the dressing over the sweet potato mixture, and toss gently. Serve immediately or it will keep, covered and refrigerated for up to 5 days.