Pound the Boneless, Skinless Chicken Thigh (4) to medium thickness about 1/2 an inch thick.
Place chicken in a large zliploc bag. Add Soy Sauce (2 tablespoon) and Worcestershire Sauce (2 tablespoon). Mix well. Let marinade for at least 3 hours or overnight.
In a small saucepan, melt the Butter (2 tablespoon) over medium heat. Add Onion (1) and Button Mushroom (1/4 cup). Saute until onions are soft, approximately 2 minutes.
Add Ketchup (4 tablespoon), Chicken Bouillon Powder (1 teaspoon), Water (4 tablespoon), Brown Sugar (1 tablespoon) and Corn Starch (1 teaspoon). Bring to boil, stirring until the sauce thickens up a little bit. Turn off heat; set aside.
Heat up cooking Oil (to taste) over medium heat in a skillet or large frying pan.
Dip chicken in All-Purpose Flour (2 cup), dip in Egg (2) wash, then into Panko Breadcrumbs (2 cup). Fry chicken till golden brown on each side.
Serve with french fries and your choice of veggies. Pour sauce over chicken just before serving.