Scrub and halve potatoes lengthwise.
Bring large pot of salted water to boil. Add potatoes; cover and return to boil. Cook for 15 minutes or until fork-tender.
Dressing: In large bowl, whisk together buttermilk, yogurt, dill, vinegar, oil, mustard, salt and pepper.
Drain potatoes; let cool for 5-10 minutes or until no longer steaming. Cut potatoes into bite-size pieces; gently stir into dressing along with radishes, onions and yellow pepper.
Per Serving: about 125 calories, 3 g protein, 3 g fat, 23 g carbohydrate,
Source: Canadian Living magazine, Aug 95 Presented by Elizabeth Baird, Canadian Living Test Kitchen, in "Veggie Pleasures"