Prepare onion. Peel the red onion and slice it thinly. A mandolin works well for this, but I typically just use a sharp chef’s knife.
Combine vinegar and spices. In a mason jar or bowl with a lid, add 1 cup vinegar, 2 tablespoons of salt, peppercorns, coriander seeds, oregano, and bayleaf. Cover and shake well until salt is dissolved.
Add onion. Pack in the sliced onions to the jar with the vinegar and spices. Add the remaining vinegar and remaining tablespoon of salt. Cover and shake again. Let stand at room temperature for at least 30 minutes, but they will taste even better if you let them sit for at least two hours, or overnight. The longer they sit, the more pink and flavorful they become.
Serve and enjoy. When ready to enjoy, be sure to shake off excess spices from the onion slices (coriander seeds can let off an explosion of flavor!). Onions will last in the refrigerator for up to one month. They’ll still be good after this, but will start to fade in color.
A Note from Lola
ON SALT
I always use Crystal Diamond Kosher Salt because it’s less salty than other salts, so if you're using something other than this, be sure to taste as you go and be careful not to over salt.
ON INGREDIENTS AND IMPROVISING
The ingredients you’ll need to make this recipe include vinegar, coarse kosher salt, black peppercorns, coriander seeds, dried oregano, bay leaf, and of course, red onion. While all of the different spices infuse wonderful flavor, if you don’t have peppercorns, coriander seeds, or a bayleaf in your pantry, you can still make delicious pickled onions with just the vinegar, onions, and coarse salt (yes, you’ll need coarse salt).
ADDITIONAL NOTE ON SODIUM
The sodium content reflects the total sodium used in the pickling process. However, the actual sodium content per serving of onions is lower, as the pickling liquid is not typically consumed.