In large saucepan, combine half & half, Honey Thyme Mustard, cornstarch, salt and pepper; mix until well blended and cornstarch is dissolved.

Stir potatoes and onion into cream mixture; bring to a boil over medium heat, stirring frequently to coat potatoes.

Pour potatoes and cream into well-greased 2 quart shallow baking dish. Sprinkle top with grated cheese.

Bake at 375°F, 1 hour and 15 minutes, until potatoes are tender when pierced with a knife.