Important Note: Use caution when handling jalapeños. It's recommended to wear gloves during preparation and avoid touching your face or eyes.
Wash the jalapeños thoroughly and trim off the stem ends. Optionally, to reduce spiciness, core or partially core the peppers to remove some of the inner membrane and seeds.
Slice the jalapeños into ¼-inch round slices.
On the stovetop, in a large non-reactive pot, combine apple cider vinegar, sugars, and seasonings. Simmer the mixture over medium-high heat for about 5 minutes until all ingredients are fully combined. Stir regularly as the syrup tends to bubble.
Add the sliced jalapeños to the syrup mixture. Bring to a boil, then reduce the heat and simmer for 5 minutes, stirring occasionally.
Using a slotted spoon or tongs, transfer the cooked jalapeño slices into clean jars, leaving the syrup in the pot. Fill the jars almost to the top, leaving at least ½ inch of headspace. Pack the jalapeños lightly.
Return the syrup in the pot to a boil, then simmer for 8 to 10 minutes to reduce and thicken.
Ladle the hot cowboy candy syrup into the jars over the jalapeño slices, leaving ½ to ¼ inch of headspace.
Follow specific canning instructions, or if not canning, allow the jars to cool and then refrigerate. Consume within 3 months for optimal freshness.
For best flavor, wait at least one week if refrigerating or 3 to 4 weeks if canned before enjoying your homemade cowboy candy.