Two-Toned Potato Salad

Cook Yukon Gold and sweet potatoes, covered, in a large saucepan in enough boiling water to cover for 10 to 12 minutes or until just tender. Drain well; cool to room temperature.

Meanwhile, combine mayonnaise, mustard, milk, thyme, and pepper in a large bowl. Add the potatoes, celery, and scallions. Toss to coat. Cover and chill at least 4 hours or up to 24 hours. Gently stir in bacon just before serving.