In a large bowl, stir together 1 tbsp garlic, 1 tbsp ginger, ½ cup soy sauce, and the sesame oil (1 tbsp).
2 tbsp garlic, 2 tbsp ginger, 1 cup soy sauce, 1 tbsp sesame seed oil
Place the chicken in a large freezer baggie (or a baking dish), and pour the marinade over the chicken. Move the chicken around to fully coat. Seal the baggie (or cover the dish with foil), and refrigerate for 1 hour, or even better, overnight.
8 chicken thighs
Preheat oven to 350°F.
Remove the chicken from the marinade and brush off any garlic or ginger. Place on a baking rack on a baking pan that is lined with foil.
Bake the chicken (skin-side up) until the internal temperature reaches 160°F, about 35 to 40 minutes.
While the chicken is baking, make the sauce by sautéing the garlic and ginger (1 tbsp each) in the olive oil in a medium saucepan over medium heat until soft, about 4 minutes. Stir in the remaining soy sauce (½ cup), pineapple juice, mirin, and brown sugar. Bring to a boil and then reduce heat to medium.
1 tbsp olive oil, ¼ cup pineapple juice, ½ cup mirin, ¼ cup brown sugar
Make a slurry by combining 1 tbsp water with 1 tbsp cornstarch. Stir until smooth. Stir into the sauce and cook until thickened. The consistency should be like a glaze. If the sauce is too thin, add another cornstarch slurry (1 tbsp water with 1 tbsp cornstarch). Remove from heat and divide the sauce into two separate bowls.
1 to 2 tbsp cornstarch
Remove the chicken from the oven and increase the temperature to 425°F. Brush half of the teriyaki sauce all over the chicken. Bake for another 10 minutes until the skin is darkened and browned on the edges.
Remove from the oven and serve at once garnished with sesame seeds and green onions, if using. Serve over steamed rice, if desired.
Sesame seeds, 2 tbsp green onions, Steamed rice