Can anyone direct me to a recipe for a creamy potato gratin - or any other suitable potato dish to serve with rack of lamb? The in-laws are coming for dinner and I've decided on the red current jelly/wine sauce rack of lamb from epicurious. The potato gratins I've made in the past all turned out on the dry, dense side. My other 2 sides will be creamed spinach and carrots in a sour cream horseradish sauce. Thanks!