Wash and Dry: Wash the jalapeños thoroughly and pat them dry.
Slice: Cut off the stems and slice the jalapeños into rounds or halves, depending on your preference.
Making the Brine
In a saucepan, combine the vinegar, water, garlic, sugar, and salt.
Bring the mixture to a boil, stirring until the sugar and salt are dissolved.
Remove the saucepan from heat and let it cool for a few minutes.
Pickling the Jalapeños
Place the mason jar, and add smashed garlic, black peppercorns, and mustard seeds at this stage.
Then pack the sliced jalapeños tightly.
Pour the hot brine over the jalapeños, making sure they are fully submerged. Leave about ½-inch of headspace at the top of the jar.
Seal the jar with a lid and let it cool to room temperature.
Once cooled, store the jar in the refrigerator.
Notes
Store the leftover in the:Refrigerator: Last for 5-6 weeks.Freezer: Freezing preserves them for up to three months, but may soften the texture.Thawing: Best to thaw in the refrigerator.