Cut the tofu block in half and then cut out a circle using a cookie cutter. (Cut into squares if tofu is a different size)
Combine dark soy, sesame oil, black pepper and salt.
Marinate tofu in 2/3 of the sauce for a minimum of 10 mins.
Heat up a griddle/frying pan till very hot.
Place marinated tofu pieces on a pan and cook for 2 minutes on each side. Brush cooked sides with remaining sauce.