Combine sugar, apple cider vinegar, garlic powder, turmeric, and ground cayenne in a medium pot. Stir to combine. Bring to a boil. Once it reaches a boil, reduce the heat and simmer for five minutes.
Remove the pot from the heat. Transfer the peppers to a glass jar using a slotted spoon. Ladle the cooking syrup into the jar, covering the peppers by about ½ inch.
Allow peppers to cool in the jar. Cover with a lid and refrigerate for up to two months.
Candied jalapeños can be eaten right away but they taste better after a few days. The flavor develops over time.