In a medium saucepan, combine apple cider vinegar, honey, red pepper flakes, salt, and black peppercorns. Add smashed garlic cloves. Stir gently and heat over medium until gently simmering for about 3-5 minutes.

Add carrot sticks to the simmering pickling liquid. Stir to coat and simmer for 3-4 minutes until they start to soften but retain some crunch.

Remove from heat and let cool for about 10 minutes. Transfer carrots to a clean jar, ensuring they are packed closely together.

Pour hot pickling liquid over the carrots until fully submerged. Leave half an inch of space at the top.

Seal the jar tightly and refrigerate. Let sit for at least 24 hours, ideally up to two weeks, to enhance flavors.