2 cups yukon potatoes, quartered (about 10 ounces)
2 cups small red potatoes, quartered (about 10 ounces)
2 cups small blue potatoes, halved lengthwise (about 10 ounces)
1/4 cup finely chopped red onion
2 tablespoons chopped fresh parsley
1 tablespoon chopped fresh dill
1 tablespoon chopped fresh chives
3 hard-cooked large eggs, finely chopped
1/4 cup red wine vinegar
2 tablespoons olive oil
1 1/4 teaspoons salt
2 teaspoons Dijon mustard
1/2 teaspoon freshly ground black pepper
1 garlic clove, minced
Note: Blue potatoes are starchier than the others and tend to bleed, so cook them separately. If you need to, prepare this dish a day ahead, but add the blue potatoes just before serving. If your potatoes are larger than the ones we call for, cut them to a uniform size.