Chicken-Asparagus Negimaki

Preheat broiler. Line a rimmed baking sheet with foil and set a wire rack on top. Whisk soy sauce, mirin, miso, garlic, and ginger in a small saucepan. Bring to a boil; reduce heat to medium and simmer briskly, stirring often, until thickened and mixture measures 1/2 cup, about 5 minutes. Stir in lemon juice and sesame oil. Let cool slightly. Transfer 2 Tbsp. sauce to a small bowl and set aside.

Meanwhile, cook asparagus in a large deep skillet of boiling salted water until crisp-tender, about 3 minutes; transfer to a large bowl of ice water and let cool. Drain and pat dry.

Cut each flattened chicken breast lengthwise into 2 pieces. Arrange on a work surface. Brush top of chicken with sauce. Mix 2 Tbsp. scallions and 1 tsp. sesame seeds to a small bowl. Sprinkle remaining scallions and sesame seeds evenly over chicken. Place 1 asparagus spear lengthwise on top of each chicken piece (asparagus and chicken should be about the same length). Tightly roll meat around asparagus. Place bundles, seam side down, on prepared wire rack.