3 two potato mustard dressing Recipes

boiling potatoes (preferably yellow-fleshed),quartered lengthwise and cut crosswise into 3/4-inch pieces, sweet potatoes ,quartered lengthwise and cut crosswise into 3/4-inch pieces, white-wine vinegar, dijon-style mustard, olive oil, chopped onion, chopped red bell, chopped sweet gherkin

red-skinned potatoes, quartered, cubed peeled sweet potato, olive oil, buttermilk, mayonnaise, chopped shallots, chopped fresh chives, dijon mustard, black pepper, salt, chopped celery