Ingredients

• 1 cup mayonnaise
• 1/4 cup coarse-grained Dijon mustard
• 2 tablespoons white wine vinegar
• 1 tablespoon minced canned chipotle chilies
• 1/2 cup dark beer
• 1/4 cup olive oil
• 2 tablespoons chopped garlic
• 2 tablespoons red wine vinegar
• 1 teaspoon Worcestershire sauce
• 3/4 teaspoon hot pepper sauce (such as Tabasco)
• 2 pounds skirt steak, trimmed of fat
• 2 red onions, thinly sliced into rounds
• 2 tablespoons fresh lemon juice
• 3/4 teaspoon coarse salt
• 3 tablespoons butter
• 1 large shallot, sliced
• 3/4 pound assorted mushrooms (such as crimini and oyster), sliced
• 1/4 cup Sherry wine vinegar
• 1/4 cup olive oil
• 10 ounces mixed baby lettuces

Instructions

1. Whisk all ingredients in small bowl to blend. Season dressing to taste with salt and pepper. (Can be prepared 1 day ahead. Cover and refrigerate.)
2. Make steak: Whisk first 6 ingredients to blend in 13x9x2-inch glass baking dish. Add steaks to marinade; turn to coat. Cover and refrigerate at least 8 hours.
3. Whisk first 6 ingredients to blend in 13x9x2-inch glass baking dish. Add steaks to marinade; turn to coat. Cover and refrigerate at least 8 hours.
4. Make salad: Combine onions, lemon juice and coarse salt in medium bowl. Let stand 1 hour, tossing occasionally. Prepare barbecue (medium-high heat). Remove steaks from marinade. Sprinkle with salt and pepper. Grill about 3 minutes per side for medium-rare. Transfer steaks to work surface. Melt butter in heavy large skillet over medium-high heat. Add shallot and mushrooms; sauté until well browned, about 7 minutes. Add vinegar to skillet and bring to boil, scraping up browned bits. Remove from heat; mix in oil. Season mushroom mixture to taste with salt and pepper. Combine lettuces, onions and mushroom mixture in large bowl; toss. Divide lettuce mixture among 6 plates. Thinly slice steaks across grain; arrange atop lettuce mixture. Drizzle some of aioli over salads. Pass remaining aioli separately.
5. Combine onions, lemon juice and coarse salt in medium bowl. Let stand 1 hour, tossing occasionally.
6. Prepare barbecue (medium-high heat). Remove steaks from marinade. Sprinkle with salt and pepper. Grill about 3 minutes per side for medium-rare. Transfer steaks to work surface.
7. Melt butter in heavy large skillet over medium-high heat. Add shallot and mushrooms; sauté until well browned, about 7 minutes. Add vinegar to skillet and bring to boil, scraping up browned bits. Remove from heat; mix in oil. Season mushroom mixture to taste with salt and pepper.
8. Combine lettuces, onions and mushroom mixture in large bowl; toss. Divide lettuce mixture among 6 plates. Thinly slice steaks across grain; arrange atop lettuce mixture. Drizzle some of aioli over salads. Pass remaining aioli separately.