Teriyaki Beef

6 Servings
Grill the steak about 20 minutes after the sweet potatoes go into the oven.
1/3 cup soy sauce
1/2 cup mirin
1/2 cup sake
1/3 cup sugar
4 scallions, minced
Four 1/4-inch-thick slices of fresh ginger, smashed
4 garlic cloves, smashed
1 tablespoon plus 2 teaspoons Asian sesame oil
1-1/2 pounds sirloin steak in 1 piece, cut about 1 inch thick
Salt and freshly ground pepper

1. In a saucepan, combine the soy sauce, mirin, sake, sugar, scallions, ginger, garlic and 2 teaspoons of the sesame oil. Bring to a boil over moderate heat and cook until reduced to 1-1/4 cups, 8 to 10 minutes. Strain the sauce into a small bowl.

2. Light a grill or preheat the broiler. Brush the steak with the remaining 1 tablespoon of sesame oil and season generously with salt and pepper. Grill or broil the steak, basting with some of the sauce, for 4 to 5 minutes per side for medium rare. Let rest for 5 minutes, then thinly slice the steak on the diagonal and serve with the Sweet Potato Packets. Pass the remaining sauce separately.