Cranberries and apple simmer with red onion, ginger and mustard seeds for a spiced variation on traditional sauce. Try it on a sandwich with leftover turkey.
Finely shred zest from the orange (should have about 2 teaspoons); set aside. Cut 1/4-inch off the top and bottom of the orange. With a sharp knife, remove skin and white membrane from orange. Working over a medium saucepan (to catch juice), separate and remove segments from orange, setting the segments aside on a cutting board. Cut segments into small pieces and set aside. Squeeze remaining membrane over pan to extract any remaining juice.
Add brown sugar, vinegar, water, onion, ginger, mustard seeds, salt and crushed red pepper to saucepan. Bring to boiling over medium-high heat. Add cranberries and orange zest. Return to boiling; reduce heat. Cook, uncovered, for 7 minutes, stirring occasionally. Add apple and cook for 3 minutes more or until apple is just tender.
Remove from heat, remove and discard ginger and stir in reserved orange segments. Serve warm or refrigerate, covered, for up to 2 days. Bring to room temperature before serving, if chilled.