Wash potatoes; scrub thoroughly with a vegetable brush. Cut tiny new potatoes into quarters or the medium potatoes into 1-inch pieces.
Place potatoes in a 1-1/2-quart microwave-safe casserole. Add margarine or butter, teriyaki sauce, garlic salt, Italian seasoning, black pepper, and red pepper. Toss to combine. Cover; micro-cook on 100% power (high) for 11 to 15 minutes or until potatoes are tender, stirring twice during cooking. Stir before serving.
Garnish with snipped rosemary and serve with sour cream, if desired. Makes 5 side-dish servings.