In a large skillet cook potatoes and fresh green beans, if using, in water, covered, about 15 minutes or until potatoes and beans are tender. (If using frozen beans, add to potatoes the last 5 minutes of cooking.) Drain well.
Meanwhile, in a small saucepan stir together yogurt, flour, mustard, dillweed, and pepper. Cook and stir until thickened and bubbly. Pour over vegetables in skillet. Stir in ham. Heat through. Makes 4 servings.