In a food processor, pulse scallions, garlic, lemon zest, ginger, and cilantro until finely chopped. Add oil, harissa, lemon juice, and 1 tablespoon salt; process until a paste forms.
Using kitchen shears, remove backbone from chicken. Place, breast-side up, on a cutting board; press down with your hands to flatten. Spread half of paste under and over skin and over cavity side. Arrange onions in a large cast-iron skillet. Place chicken on top, skin-side up. Let stand at room temperature 1 hour, or refrigerate, uncovered, up to 8 hours. (Bring to room temperature before roasting.)
Preheat oven to 425 degrees. Arrange half of lemon rounds on chicken. Roast 25 minutes. Combine remaining paste and marmalade; brush chicken with mixture and top with remaining lemon rounds. Roast until a thermometer inserted in thickest part of thigh (not touching bone) reads 155 degrees, about 20 minutes more. Let stand 10 minutes; serve.
In a food processor, pulse scallions, garlic, lemon zest, ginger, and cilantro until finely chopped. Add oil, harissa, lemon juice, and 1 tablespoon salt; process until a paste forms.
Using kitchen shears, remove backbone from chicken. Place, breast-side up, on a cutting board; press down with your hands to flatten. Spread half of paste under and over skin and over cavity side. Arrange onions in a large cast-iron skillet. Place chicken on top, skin-side up. Let stand at room temperature 1 hour, or refrigerate, uncovered, up to 8 hours. (Bring to room temperature before roasting.)
Preheat oven to 425 degrees. Arrange half of lemon rounds on chicken. Roast 25 minutes. Combine remaining paste and marmalade; brush chicken with mixture and top with remaining lemon rounds. Roast until a thermometer inserted in thickest part of thigh (not touching bone) reads 155 degrees, about 20 minutes more. Let stand 10 minutes; serve.