Preserved Lemon-Rubbed Rack of Lamb with Israeli Couscous

1 preserved lemon

1/3 cup finely chopped flat-leaf parsley

3 garlic cloves, finely chopped

2 8-rib frenched racks of lamb (each about 1 1/2 pound), trimmed of all but a thin layer of fat, brought to room temperature fine sea salt freshly ground black pepper

1 teaspoon vegetable oil COUSCOUS:

3 tablespoons extra-virgin olive oil, divided heaping

1/3 cup chopped red onion

1 1/2 cups Israeli couscous (sometimes called pearl couscous)

1 3/4 cups plus 1 tablespoon water

1/4 teaspoon crumbed saffron threads fine sea salt

1/4 cup finely chopped flat-leaf parsley finely grated zest of

1 lemon freshly ground black pepper