Mix sesame paste, white miso, and milk until smooth, and add Sriracha sauce (depending on your taste) and sesame seed.
* If you use common miso but not white miso, needed to reduce it and add a little bit sugar.
Microwave the sauce above for 20 seconds before serving.
Heat a grill pan over medium-high heat and coat pan with cooking spray. Place chicken in pan, cook 5 minutes on each side or until done. Serve with the creamy sauce and sprinkle sesame seed as garnish.
Here are some pictures step by step. http://daidokoro.mominaina.com/10437