Rinse off the fish and pat dry with a paper towel.
Line a baking dish with foil and spray with a little non-stick spray.
Lay the fish on the foil (skin side down if using salmon with skin).
In a small bowl, mix the soy sauce, brown sugar, and 1 tsp of ground black pepper. Stir well. You want the sauce to thickly coat the back of a spoon. If your sauce if too thick, add a little extra soy. If it is too thing, add a little more brown sugar.
Spoon the soy mixture over the fish. Sprinkle each piece with a little salt and pepper.
Cook for 15 minutes or until the fish becomes flaky and separates easily with a fork.