500gm boneless chicken thighs
2/3 cup mirin (Japanese sweet rice wine)
1 cup soy sauce (reduced sodium)
4 1/2 tsps rice vinegar
1 tsp sesame oil
1/3 cup white sugar
7 cloves garlic, minced
1 tablespoon fresh ginger, minced
1 dash red pepper flakes
1 dash black pepper to taste
Over high heat, bring mirin in a medium saucepot to a boil. Once at a boil, turn heat down to medium-low and simmer for 10 minutes.
Add soy sauce, rice vinegar, sesame oil, and sugar. Stir until fully incorporated. If you desire a thicker teriyaki sauce, add 2 teaspoons of cornstarch dissolved in a little bit of water to the sauce.
Add garlic, ginger, pepper flakes, and pepper.
Continue to simmer for 5 more minutes. Remove from heat and let cool for 10 minutes.
Transfer all but 1/4 cup of the cooled teriyaki sauce to a sealable plastic bag, along with the chicken. The reserve sauce can be used either as a baste at the end of the cooking process or as a dipping sauce.
Refrigerate the marinade and the chicken for at least an hour but preferably a day. The longer you marinade your chicken, the juicier and more flavorful it will eventually turn out.
When you're ready to start cooking, remove the chicken from the sealable bag and set a burner at medium heat. Discard the marinade that came in contact with the chicken.
Cook chicken in a large pan for 6 minutes, covered, without flipping.
Flip the chicken and cook, covered, for another 6 minutes.
Baste the chicken with the remaining teriyaki sauce, flip it, and sear it on medium-high for 2-3 minutes per side, uncovered.
Serve with steamed rice, asparagus, or crispy edemame.