Cebolete (Pickled Red Onions)

Slice the red onions into very thin half-moons using a sharp knife or a mandoline.

Transfer the onions to a sieve and pour hot water over them. This reduces the sharp bite of the onion. Let them drain well.

In a separate container, mix the vinegar, olive oil, salt, oregano, Calabrian chili flakes, and chopped parsley to create the marinade.

Place the drained onions into a jar, add all of the marinade, and mix well so the seasoning is distributed evenly.

Cover and let it rest for at least 1 hour before serving. For even more intense flavor, prepare it a day in advance and store it in the fridge.