slice unpeeled orange into 8ths and remove seeds, place 1/2 orange slices and 1/2 cranberries in food processor with 1/2 of the stevia powder and process until mixture is evenly chopped, almost pureed. transfer to bowl and repeat with remaining orange, cranberries and stevia. add sugar to taste if desired, but give the relish a chance to sit first and meld the flavors. you may not want to add sugar at all. for best flavor make a day ahead and refrigerate.