Peel and core the apple and then cut it into chunks. Leaving the peel on the orange, cut it into chunks and remove any seeds.
One at a time, separately pulse the cranberries, chunks of orange, and chopped apple in the food processor (or blender). Lightly pulse, do not puree ingredients.
In a mixing bowl, mix together the cranberries, orange and apple.
Toss the relish with sugar. Refrigerate for at least 2 hours for best results.
Notes
Serving size is based on serving as a topping. If your guests love this relish as a side, consider doubling the recipe.