Ingredients

• 1/4 cup Worcestershire sauce
• 1/4 cup olive oil
• 1 teaspoon chopped fresh thyme
• 1/4 teaspoon salt
• 2 medium onions (preferably 1 red and 1 sweet), cut into 1/4-inch-wide wedges
• 2 tablespoons olive oil
• 3/4 teaspoon salt
• 1/2 teaspoon black pepper
• 1 1/2 pounds skirt steak
• 5 ounces arugula (10 cups loosely packed), torn if large
• Special equipment: a grill basket

Instructions

1. Whisk together Worcestershire sauce, oil, thyme, and salt.
2. Grill onions and steak: Prepare a gas grill for direct-heat cooking over moderately high heat. Toss onions with 2 tablespoons oil, 1/4 teaspoon salt, and 1/4 teaspoon pepper. Cut steak into 4 pieces and sprinkle with remaining 1/2 teaspoon salt and 1/4 teaspoon pepper. Oil grill rack, then grill steak, covered, turning over once, 6 to 10 minutes total for medium-rare. Transfer to a cutting board and let stand while onions cook. Grill onions in grill basket, covered, stirring occasionally, until charred and tender, 6 to 8 minutes.
3. Prepare a gas grill for direct-heat cooking over moderately high heat.
4. Toss onions with 2 tablespoons oil, 1/4 teaspoon salt, and 1/4 teaspoon pepper. Cut steak into 4 pieces and sprinkle with remaining 1/2 teaspoon salt and 1/4 teaspoon pepper.
5. Oil grill rack, then grill steak, covered, turning over once, 6 to 10 minutes total for medium-rare. Transfer to a cutting board and let stand while onions cook.
6. Grill onions in grill basket, covered, stirring occasionally, until charred and tender, 6 to 8 minutes.
7. Assemble salad: Toss arugula and onions with some of dressing. Slice steak and serve, drizzled with dressing to taste, with arugula salad.
8. Toss arugula and onions with some of dressing. Slice steak and serve, drizzled with dressing to taste, with arugula salad.