Trim excess fat and tendons from the chicken thighs and pat dry with paper towels. Make 2cm-wide cuts on the skin side, pierce with a fork in several places, and season both sides with salt and pepper.

Cut potatoes into bite-sized pieces, soak in water, and drain. Place in a microwave-safe container, cover loosely with plastic wrap, and microwave at 600W for about 6 minutes until soft. Mix with butter and a pinch of salt and pepper.

Heat half the salad oil (1/2 tbsp) in a frying pan and place 2 chicken thighs skin-side down. Press occasionally with tongs or a spatula and cook over medium heat until the skin is crispy.

Flip the chicken and cook over medium-low heat for 6–8 minutes until cooked through. Add half the steak soy sauce (3 tbsp) and coat both sides. Repeat for the remaining 2 chicken thighs.