I love the combination of chocolate and orange and they unite wonderfully in this recipe. We usually make this for Christmas but it would be good anytime of the year. If you cannot find orange and tangerine marmalade, substitute orange marmalade. I like to drizzle chocolate ganache over the marmalade glaze which creates a beautiful presentation. Make the cheesecake 1-2 days in advance to allow the flavors to bloom. From Gourmet magazine, January 1995.