- Combine sugar, water,red wine vinegar, cinnamon and nutmeg in a medium nonreactive saucepan; bring to a boil.
- Add cherries and cook for 1 minute.
- Stir in cranberries; return to a boil.
- Reduce heat and simmer until about half the cranberries pop, 10 to 12 minutes.
- Remove from the heat.
- Stir in walnuts and orange zest.
- Let cool completely.
- (The marmalade will thicken as it cools.)
- Serve at room temperature or chilled.