This recipe fills two 5 ounce jars, but is easy to scale up or down. You're also free to use one larger jar - since this is not a canning recipe, you do not have to carefully balance the pH in the ingredients.
Optional: sterilize your jars by rinsing them with boiling water (I place the jars and lids in a large bowl and then pour boiling water over them, filling the jars, but not submerging them). Even though this recipe is *not* for canning, sterilizing the jars will help the pickles keep longer in the fridge.
Slice the jalapeño peppers into thin slices. Remember that most of the heat of a chili pepper is in its seeds and ribs - remove some or all to reduce heat. Pack into jars as you go, filling the jars to about an inch away from the top. Add the onion, garlic, and oregano (or layer as you're adding jalapeño slices).
Bring the vinegar, water, sugar, and salt to boil in a 2 qt pot. Remove from heat and stir until the sugar and salt are completely dissolved.
Pour the vinegar solution over the jalapeños, leaving 1/2" headroom in each jar. Affix the lids, tightening to finger-tip tightness, and let cool. When the jars are no longer hot, move to the refrigerator or freezer.
Sugar reduces the capsaicin heat of the peppers - use more or less sugar than called for, to taste. Jalapeno peppers vary drastically in heat from crop to crop, and even pepper to pepper from the same plant. If you need to carefully regulate the heat of the pickles, I'd suggest tasting a sliver from each pepper, so you can gauge the overall heat of the finished product.
Refrigerator Pickled Jalapenos was originally published on https://soupaddict.com/refrigerator-pickled-jalapenos/