In a large bowl, mix the peanut butter, honey, tamari or soy sauce, garlic, ginger, sesame oil, and sriracha (if using). Stir until the sauce is smooth and well combined. It should be thick but pourable, with a deep savory aroma and just the right balance of sweet and salty.
Add the chicken thighs to the bowl and coat them fully with the marinade. Make sure every piece is well covered. Once coated, cover the bowl and refrigerate for at least an hour. This helps the flavors soak deep into the chicken, making it juicy and flavorful after baking.
Preheat your oven to 180°C (350°F). Transfer the marinated chicken thighs into an oven-proof dish and cover it tightly with a lid or foil. Bake for 20 minutes covered. Then, remove the lid, stir the sauce gently, and return the dish to the oven uncovered for another 10 to 15 minutes. The chicken should be cooked through and the sauce golden and sticky.
Once done, serve the chicken hot with cooked noodles and steamed or stir-fried vegetables. Spoon over some of that sticky sauce from the bottom of the dish—it’s packed with flavor. Sprinkle with chopped spring onion, coriander leaves, and sesame seeds just before serving for a fresh, crunchy finish.