Japanese Chicken Gratin

Preheat oven to 200 degrees Celsius. Cut chicken thigh into 2cm pieces. Dice onion. Slice shiitake mushrooms.

In a large frying pan, melt 20 grams of butter over medium heat. Add chicken thigh and cook until lightly browned. Add onion and sauté until softened, about 5 minutes. Add shiitake mushrooms and cook for another 3 minutes.

Pour in sake and koikuchi soy sauce, stirring to combine. Season with 1 gram of salt and black pepper. Remove from heat and set aside.