Chop the onion vertically in half, then slice it crosswise, (against the grain).
Put the onion in a resealable container, fill with enough vinegar to cover the onions, and store in the refrigerator. Marinate for 1 to 2 days, until tender.
Use whatever vinegar you have on hand. Since this uses a lot of vinegar, I use grain vinegar.
Mix it with natto. I top mine with about triple the amount of natto. I also drizzle on some of the vinaigrette.
It's a very versatile dish. Use it as topping for tofu or other dishes, mix it into potato salads, etc.
In the summer, put a layer between rice in your obento to prevent the rice from spoiling.
Aside from improving blood circulation, pickled onion helps control high blood pressure, helps regulate the bowels, and reduces excess sugar and fat, making it effective for dieters.
Story Behind this Recipe
I heard from my husband that pickled onions are good for you, so now it's become a staple dish in our home.
For those who aren't quite partial to vinegar, use 1 part vinegar to 1 part soy sauce, or add sugar or dashi stock to make it milder. You can use the leftover vinaigrette for vinegar dishes or to make ponzu or dressing. Pickling eliminates the sharpness of the onion and highlights the sweetness. See Recipe ID: 1222941.