1-First, prepare the pickling liquid by combining 1 cup apple cider vinegar, ½ cup water, ⅔ cup sugar, 1 tablespoon kosher salt, 1 teaspoon yellow mustard seeds, and 2 garlic cloves in a pot. Bring this mixture to a boil over medium-high heat to dissolve the sugar and salt, then boil for 1-2 minutes and remove from heat. Let it cool slightly while you move to the next step.

2-Next, thinly slice the 2 lbs of sweet peppers and the 1 onion if you’re using it, and remove the pepper seeds if you want a milder taste. Pack the sliced peppers and onions firmly into a clean mason jar to ensure they fit well.

3-Pour the warm pickling liquid over the packed veggies, making sure everything is fully submerged, and tap the jar to release air bubbles. Seal the jar, let it cool to room temperature, and then refrigerate it. The pickled peppers will be ready after 24 hours, giving you a tasty addition to your meals with minimal effort.