1 fresh serrano chile, chopped (about 2 teaspoons; including seeds)
Accompaniment: steamed rice
Directions
Preheat broiler.
Pat steak dry and season with 1 teaspoon salt and 1/2 teaspoon pepper. Broil on a broiler pan 4 to 6 inches from heat, turning once, about 6 minutes total for medium-rare. Transfer steak to a cutting board and let rest 5 minutes before slicing.
While steak rests, stir together remaining ingredients until sugar has dissolved. Serve sliced steak with sauce.