Wearing gloves for safety, remove and discard the stems from the jalapeño peppers. Slice each pepper into 1/4-inch thick rounds and transfer the slices to a bowl. Set aside until ready to use.

In a large pot set over high heat, combine the apple cider vinegar, white sugar, light brown sugar, ground turmeric, garlic powder, celery seed, and ground cayenne. Stir well to dissolve the sugars. Bring the mixture to a boil, then reduce the heat and let it simmer gently for about 5 minutes. I always make sure to stir occasionally so the sugars don’t stick to the bottom.

Add the sliced jalapeños from Step 1 into the simmering syrup. Increase the heat to high and bring to a simmer. Cook the peppers in the hot syrup for exactly 4 minutes to soften them slightly and infuse them with flavor.

Use a slotted spoon to transfer the cooked jalapeño rounds into clean, sterile canning jars. Fill each jar up to 1/4-inch from the rim to leave space for the syrup. Make sure the jars aren’t overfilled.

Return the pot with the syrup to high heat and boil for about 6 to 7 minutes, allowing it to thicken slightly. Remove from heat and let the syrup cool for about 3 minutes. Then, using a ladle or a pitcher with a spout, carefully pour the hot syrup into the jars over the jalapeños. Make sure the slices are completely submerged. I like to use a chopstick to gently poke down into the jars and release any air bubbles, which helps everything stay fresh.

Wipe the rims of the jars with a clean, damp paper towel to ensure a good seal. Add the two-piece lids and seal the jars tightly. Place the jars in the refrigerator and let them chill for at least 2 weeks, or ideally up to one month. The flavors will deepen and improve the longer they sit.