1/2 cup soy sauce
1/2 cup sweet sherry, or mirin
1/4 cup sugar
4 salmon steaks, about 1-inch thick (about 2 pounds in all)
Heat the broiler or light the grill. If broiling, line a broiler pan or baking sheet with aluminum foil and lightly oil the foil.
In a medium stainless-steel saucepan, bring the soy sauce, mirin, and sugar to a boil, stirring. Reduce the heat and simmer, stirring occasionally, until thickened and reduced to 2/3 cup, about 10 minutes.
If broiling, put the salmon in the prepared pan. Brush the salmon with the soy-sauce mixture. Broil or grill until well browned, about 2 minutes. Turn and brush with more of the soy-sauce mixture. Continue cooking until the fish is browned and just barely done (the fish should still be translucent in the center), about 3 minutes longer. Brush with the remaining soy-sauce mixture and serve.