Cut potatoes into 1-inch pieces. Combine potato, rosemary, and 1/4 teaspoon pepper in a large bowl. Add 2 tablespoons vinaigrette; toss well. Let stand 15 minutes.
Place potato mixture in a shallow roasting pan coated with cooking spray. Bake at 400° for 40 to 45 minutes or until potato is tender. Let cool slightly.
Combine remaining 2 tablespoons vinaigrette, mayonnaise, and cheese in a large bowl, stirring well. Add roasted potato mixture and roasted pepper; toss lightly.