Using the SAUTE setting on the Instant Pot, add olive oil to the Instant Pot. Once the oil is hot brown each side of the chicken drumsticks for 5-6 minutes on each side. Season with chili flakes, cumin, salt and pepper to taste.
Add the cane vinegar, soy sauce, water, garlic, bay leaves, and pepper to taste to the Instant Pot. Cook on HIGH pressure for 13-14 minutes. Do a natural release in 10 minutes.
Remove the chicken drumsticks from the Instant Pot and set aside. Separately mix 1 tablespoon of water and 1 tablespoon of cornstarch in a small bowl. Turn on the SAUTE setting and dump the mixed cornstarch and water into the sauce. Stir to combine. Have the sauce cook for an additional 10 minutes to thicken.
Spoon the sauce over the drumsticks when serving and garnish with chopped cilantro (if using). Enjoy!