This recipe assumes a large food processor. If yours is more modestly sized, it may be better to do half at a time.
Slice one large navel orange and remove any seeds. Combine in a food processor with 250 mL sugar (1 c). Blend briefly to mix.
Add 1 L raw cranberries (4 c, about a pound). Pulse until the desired consistency is reached. The bigger the pieces, the more crunch there will be!
Let the relish sit overnight in the fridge. The sugar will draw juice out of the berries, improving both the color and the flavor.