Grilled Beef Negimaki

"This grilled beef Negimaki features tender flank steak wrapped around sweet, blanched scallions and finished with a savory-sweet glaze. Inspired by the classic Japanese steak roll, it’s packed with bold umami flavor and makes an impressive appetizer or main course. How do I know when the steak rolls are finished grilling? The internal temperature should reach 150°F to 155°F, depending on your desire for doneness. If you want your negimaki to be rare, 140 to 145°F may be desired. The char on the outside of the steak roll is a matter of personal preference and may need a little extra time for more char."