In an ungreased 2-qt. microwave-safe baking dish, layer half the potato and onion slices. Combine Italian seasoning and pepper; sprinkle half over the onion and potato layer. Drizzle with 1 tablespoon margarine. Repeat layers. Cover with vented plastic wrap. Microwave on high for 7-8 minutes or until potatoes are tender turning dish after 4 minutes.