For the marinade:
2 Tbsp reduced-sodium soy sauce
2 Tbsp brown sugar
2 Tbsp mirin
1/2 lb flank steak, very thinly sliced across the grain
20 ramps, stems only, cut into 2-inch lengths (or scallions, green and white parts); save the leaves for garnish
For the teriyaki basting sauce:
2 Tbsp agave nectar
2 Tbsp dark soy sauce
2 Tbsp mirin
2 Tbsp sake
First, put 20 small skewers or long toothpicks in a bowl of water, to soak.
In a small bowl, combine the marinade ingredients. Thinly slice the flank steak, across the grain, and marinate the slices in the marinade for 20 minutes at room temperature. (To make it easier to slice the meat, you can freeze it for 30 minutes.)
While the meat is marinating, pre-heat your grill pan or panini press. Trim the ramps or scallions into two-inch lengths. When your pan or press is hot, grill the ramps for 1 minute or until lightly charred. Remove, and set aside.
In a small, straight-sided sauté pan, heat the teriyaki basting sauce ingredients over low heat, for 2-3 minutes, until the sauce thickens slightly and the ingredients come together. Remove from heat, and set aside.
To assemble, remove strips of beef from the marinade. Place a piece of ramp (or scallion) across one end, and roll up the meat. Stick a skewer through, to keep the roll together. Repeat until all are assembled.
Place as many rolls as will fit in your panini press or grill pan. Brush each with the basting sauce. Close the press, or cook on a grill pan for 1 minute. Turn the skewers over, and brush the second side with basting sauce. Close the press, or cook in the pan for 1 minute more.
Remove, and repeat until all are cooked. Serve hot or at room temperature.