Wearing gloves, slice off the jalapeno stems. Cut the peppers into uniform 1/8-1/4 inch rounds. (Keep the seeds for more heat, remove for less).
In a large pot, combine the vinegar, sugar, turmeric, celery seed, garlic, and cayenne pepper. Bring the mixture to a boil over medium-high heat. Reduce the heat and simmer for about 5 minutes to dissolve the sugar.
Add the jalapeno slices to the pot and simmer gently for exactly 4 minutes. This allows them to soften while retaining a bit of crunch.
Remove the pot from the heat and let the mixture cool completely. Using a slotted spoon, transfer the jalapeños and syrup to clean, sterilized jars. Seal tightly.
Cowboy candy is best after it sits in the refrigerator for at least a few days, allowing the flavours to meld. It should last for several weeks in the fridge.