Assemble the salad by evenly distributing sliced onion, spring mix, carrot, radish, cucumber and apple between large mason jars. Cover and store in the refrigerator.
When you are ready to eat, add avocado and balsamic vinegar to the mason jar and shake, or empty contents into a bowl, then dress. Season with salt to taste.
Recipe Notes
For sensitive gut, and to improve digestion: Consider briefly blanching the onion, carrot, cucumber, apple, and radish in simmering water ahead of time, then chilling before adding to the salad jars.
