1-First Step: Slice the onions Start by peeling the 2 small red onions and slicing them as thinly as you can. Thin slices pickle faster and give you that crisp, tender bite people love in refrigerator quick pickled red onions. A mandoline helps make the slices even, which is great if you want consistent texture. If you do not have one, a sharp knife works just fine. Try to keep the slices as even as possible so they all finish pickling at the same time.

2-Second Step: Pack the jars Divide the onion slices between 2 or 3 clean jars. Wide-mouth glass jars are easiest to fill, and they also make serving simple later on. If you are using the optional garlic cloves and peppercorns, add them now so the flavor can spread through the brine. Do not pack the jars so tightly that the liquid cannot move around the onions. A little space helps the vinegar soak in evenly.

3-Third Step: Make the brine Place the 2 cups white vinegar, 2 cups water, 1/3 cup cane sugar, and 2 tablespoons sea salt in a pot. Warm the mixture over medium heat and stir until the sugar and salt are fully dissolved. You do not need to boil it hard. The goal is simply to make a smooth brine that blends well and helps the flavors come together. This quick heating step is one reason quick pickled red onions are so easy for beginners.

4-Fourth Step: Let the brine cool slightly Once everything is dissolved, remove the pot from the heat and let the brine cool for a few minutes. It should still be warm, but not piping hot. This helps protect the texture of the onions while still allowing the brine to work quickly. If the liquid is too hot, the onions may soften more than you want. A short rest makes a big difference in the final crunch.

5-Fifth Step: Pour the brine over the onions Carefully pour the warm brine over the onion slices in the jars. Make sure the onions are fully covered. If needed, press them down gently with a spoon so they stay under the liquid. This is an important part of making refrigerator quick pickled red onions because any exposed onion can pickle unevenly. You want every slice to get the same tangy treatment.

6-Sixth Step: Cool, cover, and chill Let the jars cool to room temperature before putting on the lids. Once they are cool, cover them and place them in the fridge. Thin slices are usually ready in about 1 hour, while thicker slices may need overnight to get fully pickled. The flavor gets better as the onions sit, so if you can wait until the next day, the taste will be even stronger and more balanced. These onions will keep for up to 2 weeks in the refrigerator.

7-Seventh Step: Serve and enjoy Use your refrigerator quick pickled red onions on tacos, salads, sandwiches, burgers, grain bowls, and Mexican dishes. They add a bright pop of color and a little sour crunch that wakes up heavy or rich foods. They are also lovely on avocado toast, pulled meat sandwiches, and roasted vegetable plates. If you like to meal prep, make a batch on Sunday and use it all week.