Pickled Red Onions Recipe by Chef Shaun 🇹🇹 Pickled red onions are a tangy and flavorful condiment made by soaking thinly sliced red onions in a mixture of vinegar, water, sugar, and salt. The acidity from the vinegar helps to soften the onions and infuse them with flavor, while the sugar adds a touch of sweetness and the salt balances the flavors. To make pickled red onions, you typically start by heating a mixture of vinegar, water, sugar, and salt until the sugar and salt dissolve. Then, you