A salad of peppery frisee (from the endive and chicory families) and baby spinach makes a perfect side dish for lunch or dinner. The addition of fresh scallions imparts a mild oniony flavor.
Whisk together lemon juice, parsley, mustard, and sugar in a large bowl; season with salt and pepper. Add oil in a slow, steady stream, whisking until emulsified; set aside.
Toss together frisee, spinach, radishes, and scallions on a large platter. Just before serving, drizzle with some of the dressing. Serve remaining dressing on the side.