Here is a recipe that uses secondary fermentation to make a probiotic-rich condiment. There is a triangulation of onion, soy sauce, and rice vinegar that becomes a powerful condiment and sauce.
It’s a very easy recipe. It actually has hardly anything to remember, except the rich, umami flavor.
Secondary fermentation is a very slow, not very obvious type of ferment. Instead of harvesting wild microbes living on the onion by making a brine, we use fermented products to create the action.
No recipe: it’s just fresh onions, with equal parts soy sauce and rice vinegar to cover!
Let’s go ahead and make it. Slice or shred the onions in any shape. I use it for a condiment so I tend to make them very thin. Or consider shredding. For the fermenting brine use equal parts rice vinegar and soy sauce.
I prefer to use live-culture soy sauce and/or vinegar.
Combine and refrigerate for 2-3 days.
Here’s my favorite way to use Japanese Pickled Onions
Russ Shulman, friend and former cooking assistant, created this breakfast favorite: beat a few eggs and thin with a bit water or dairy. Add in some cooked quinoa, salt and pepper. Then sauté in oil. Top with some of the pickled onions, a drizzle of brine, and some chopped herbs/chives.
Note: some raw onions can be fiery, sulphur bombs. Soak the sliced onions in just enough water that has a couple tablespoons of baking soda dissolved. Let soak for 15 minutes and rinse well and drain. Then add to the brine.