Rinse cranberries in a colander. Pick out any shriveled or damaged berries. Dissolve sugar in water and bring to a boil in a medium saucepan. Add the cranberries and bring to a boil. Reduce heat so that the berries boil gently and stir occasionally. The berries will begin to pop and the sauce will thicken in about 10 to 20 minutes.

When the berries are popped and the jelly has formed, remove the sauce from the heat and stir in the orange marmalade. Stir in the nuts, grated apple, and Grand Marnier, if desired. Taste and adjust ingredients. Refrigerate for at least 1 hour so flavors can blend together. Make up to 3 days in advance.