How to Make Pickled Red Onions (Quick Refrigerator Pickles)

Combine 1/2 cup apple cider vinegar, 1 cup water, 1 1/2 teaspoons salt, 1 tablespoon sugar, and a small handful of whole black peppercorns in a measuring cup or bowl. Stir until the salt and sugar dissolve completely. The brine turns a light golden color from the vinegar. No heating needed - this is a cold brine and it works just fine. Watch this step

Cut both ends off the onion, halve it from pole to pole, and peel it. Slice each half into thin half-moons - aim for about 1/8 inch. Thin enough to soften quickly in the hot water bath, but not so thin they turn to mush. Use a medium onion; a large one won't pack well and the pieces won't pickle as evenly. Put the slices in a bowl when done. Watch this step

Pour boiling water over the sliced onions in the bowl and let them sit for about 1 minute. This quick blanch does three things: it softens the raw-onion sharpness, makes the slices pliable enough to pack tightly into the jar, and kick-starts the color change to pink. Your eyes will water when the steam hits - that's normal, the volatile compounds cook off fast. After a minute, drain completely. Watch this step

Drain the hot water and pack the onions into a pint-sized wide-mouth mason jar. They've softened from the blanch and compress a bit as you push them down - cram in as much as the jar will hold. If the onions are still too hot to handle with your hands, use tongs or a fork. One medium onion fills a pint jar pretty well. Pack them snug so the brine doesn't just run straight through. Watch this step

Pour your prepared brine over the packed onions until they're fully submerged. Drop in a few whole peppercorns right into the jar - they add subtle heat and look great through the glass. Tap the jar on the counter a couple times to release any air pockets. The brine should reach close to the top of the onions. Leave the jar uncovered and set it on the counter to cool. Watch this step

Leave the jar uncovered on the counter until it reaches room temperature - roughly 30 to 45 minutes. Then put the lid on and refrigerate. They're technically ready in a few hours but taste noticeably better after an overnight rest. The color deepens to a vivid magenta as they sit. They'll keep in the fridge for up to two weeks. Pile them on tacos, grilled fish, sandwiches, grain bowls, charcuterie boards - they go on almost anything. Watch this step