In a colander, rinse the cranberries under water. Pick out any squishy or rotten cranberries. Add to the food processor bowl.
Wash the orange. Leave the orange unpeeled. (Yes, keep the rind on.) Chop into chunks so that it fits into the food processor more easily. Add the orange to the food processor bowl.
Drizzle in the honey. Add the walnuts.
If desired, add the vanilla extract. This gives the relish an orange-vanilla flavor. I like it, but it may not be what you're looking for.
Put the lid on the food processor bowl. Pulse in quick pulses. You want everything to start breaking down to the size of large crumbs. Don't let it go too far or it will turn into mush. It's okay to have a little texture, but you probably don't want the pieces too big. Use your judgment.
Store for up to a week in the refrigerator.
*For Whole30, use two large pitted Medjool dates instead of honey. I recommend chopping the dates up a little before adding them to the food processor since they can get gummy. For a vegan dish, swap the honey for maple syrup, coconut crystals, or dates.
**For Whole30, do not add vanilla extract.