Halve any large potatoes. With a vegetable peeler, peel a strip around the center of each potato. In a large saucepan cook the potatoes and onion in a small amount of boiling salted water for 12 to 15 minutes or until potatoes are just tender. Drain well.
Meanwhile, for cheese sauce in a small saucepan combine the flour, garlic powder, and pepper. Stir in the milk and the broth all at once until blended. Cook and stir over medium heat until thickened and bubbly. Cook and stir for 1 minute more. Reduce heat to low. Add the cheese; cook and stir just until cheese melts. Add the cheese sauce to the potatoes; heat through. Transfer to a serving bowl. Sprinkle with the snipped parsley, if desired. Makes 6 servings.