Ingredients:

  • 2 medium Red Onions (about 350g), peeled, trimmed, and thinly sliced
  • 1 cup (240 ml) Distilled White Vinegar (or Apple Cider Vinegar)
  • 1 cup (240 ml) Water (filtered)
  • 2 tablespoons (30 g) Granulated Sugar
  • 1 teaspoon (5 g) Kosher Salt
  • 2 Garlic Cloves, lightly smashed (optional)
  • 1 teaspoon Whole Black Peppercorns (optional)

Instructions:

  1. Sterilize the Jar: Submerge the clean jar and lid (excluding rubber seals) in boiling water for 10 minutes, or run through a hot dishwasher cycle. Let the jar air-dry completely.
  2. Slice the Onions: Using a mandoline or sharp knife, slice the red onions as thinly as possible (aim for 1/8 inch / 3mm). Thin slices pickle faster.
  3. Pack the Jar: Place the sliced onions tightly into the sterilized jar. Tuck in the optional smashed garlic cloves and peppercorns amongst the slices.
  4. Combine Brine Ingredients: In a small non-reactive saucepan, combine the vinegar, water, granulated sugar, and salt.
  5. Heat: Place the saucepan over medium-high heat. Stir constantly until the sugar and salt are completely dissolved and the mixture is just beginning to bubble around the edges.
  6. Remove from Heat: Once dissolved, remove the brine immediately.
  7. Pour Brine: Carefully pour the hot brine over the packed onions in the jar until the liquid fully covers the onions.
  8. Press and Seal: Gently press down on the onions with a spoon or fork to ensure they are fully submerged beneath the liquid (this prevents spoilage). Place the lid loosely on the jar.
  9. Cool: Let the jar cool completely to room temperature on the countertop (about 1–2 hours).
  10. Chill and Store: Once cooled, seal the jar tightly and transfer it to the refrigerator. The onions are ready to eat in 30 minutes, but the flavor is much better and deeper after chilling for at least 24 hours.