In a large zip-top bag, combine vinegars, honey, garlic, tamari or coconut aminos, marmalade, salt, and pepper. Add in drumsticks, seal bag, and toss to coat. Stash bag in fridge for 2-3 hours (or overnight) to marinate, rotating bag occasionally.
When ready to cook, preheat oven to 425°F. Cover a baking sheet in parchment paper. Remove drumsticks from bag and lay on baking sheet. Bake in preheated oven for 15-20 minutes, or until juices run clear and the internal temperature reaches 165°F.
Meanwhile, pour remaining marinade into a medium saucepan and bring to a boil. Reduce heat to low and simmer for 5-10 minutes, or until marinade is thick.
When drumsticks are finished cooking, preheat broiler. Using a pastry brush, coat drumsticks in reduced marinade. Broil for 3-5 minutes, or until browned and sticked. Flip and repeat with other side.
Before serving, sprinkle drumsticks with sesame seeds and cilantro.
Notes
You may have heard that it is unsafe to reuse a meat marinade, and this can be true. But in this case, you're keeping the meat refrigerated at all times, and then rapidly boiling the marinade afterward, which not only helps thicken the sauce, but also serves the purpose of cooking out any bad bugs that might have made it in, making it safe to use.