Slice thinly and use a suitable container

Cut very thin half-moons. Thick pieces remain sharp longer and absorb liquid unevenly. Choose a clean heatproof container that can be covered later; an arbitrary cold glass jar may crack under hot liquid. Use ordinary vinegar labeled around five percent acidity, not undiluted vinegar essence. Flavor adjustments must not be mistaken for a safe canning formula. A lid that pulls inward as it cools does not prove this preparation is shelf-stable.

Thin onion slices soften faster than thick rings. Separate the layers before adding liquid, then press them below the surface with a clean spoon without filling the jar to its rim. This quick pickle is not a tested canning process: keep the cooled jar refrigerated rather than storing it in a pantry. Portion with clean utensils and keep the remaining supply refrigerated.

Make an amount you will use

This batch covers several burgers or a taco meal. For two people, halve all quantities, including water, vinegar, sugar and salt. A small remainder is not a reason to keep adding fresh raw onions to the same aging liquid. Start each new batch with fresh liquid and note the date. For a milder topping, drain the chilled serving portion and use it sparingly instead of heavily diluting the whole brine and then expecting to store it for longer.

The recipe

Makes about 14 oz / 400 g

Ingredients

  • 2 red onions, about 9 oz / 250 g
  • ⅔ cup / 150 ml white wine vinegar, about 5% acidity
  • ⅔ cup / 150 ml water
  • 1 tbsp sugar
  • 1 tsp fine salt
  • ½ tsp black peppercorns

Method

  1. Peel onions and cut into thin half-moons. Place in a clean heatproof container without packing the rings too tightly.
  2. Bring vinegar, water, sugar, salt and peppercorns to a boil, stirring until sugar and salt dissolve. Carefully pour over onions so they are largely submerged.
  3. Cool briefly and refrigerate promptly, never leaving the container on the counter overnight. After about one hour, remove portions with a clean fork. Drain before topping food and keep the remaining onions refrigerated.

Storage

Keep refrigerated continuously at 40°F / 4°C or below and use within three days. Remove portions only with clean utensils and keep onions largely under the liquid. Do not store at room temperature, use this as a canning recipe or treat a vacuum-sealed lid as proof of safe shelf stability.

Use grilling equipment only in its intended location and follow the manufacturer’s instructions. Timing is not a substitute for checking doneness.