Both mirin and miso paste are available at most Asian markets.
1/2 cup light beer
1/2 cup mirin
1 cup white miso paste
1/4 cup sugar
2 1/2 pounds boneless salmon (skin intact), cut into 6 pieces
Olive oil spray
Salt and pepper, to taste
In a saucepan, bring the beer and mirin to a boil and cook for half a minute.
Turn down the heat, stir in the miso paste, and when it dissolves completely, add the sugar, stirring constantly. You have to take care that the marinade does not burn.
Remove the pan from the heat and let it cool.
Arrange the salmon in one layer in a deep baking dish. Pour the miso marinade on top, and turn the fish in the marinade. Cover with plastic wrap and refrigerate for up to 12 hours.
Remove the salmon from the marinade and wipe off the excess liquid.
Rinse the baking dish and wipe it dry. Set the salmon in the dish and spray it with oil. Sprinkle with salt and pepper.
Light a charcoal grill. When the coals turn gray, grill the fish, skin side down, for 3 minutes.
Turn over and continue cooking for 3 minutes more or until the fish is cooked through. SERVES 6