Another tasty recipe from Ladies Home Journal Sear Genius Barbecue Recipes.
In a zip-top bag, combine 1/3 cup lemon juice, 3 tablespoons white wine vinegar, 1/4 cup finely chopped shallots, 3 cloves chopped garlic, 1/2 cup olive oil, 1 1/2 teaspoons dried oregano, 1 1/2 teaspoons dried rosemary, 1/2 teaspoon black pepper, and kosher salt. Add a 2-pound flank steak and marinate in the fridge for 2 to 3 hours. Remove from marinade and grill over direct high heat for 5 minutes on each side for medium rare. Let steak rest about 10 minutes before slicing.
In a blender or small food processor, blend 1 anchovy fillet (or 1/4 teaspoon anchovy paste), 2 cloves garlic, 1/2 teaspoon kosher salt, 1 tablespoon lemon zest, 2 tablespoons lemon juice, and 2 tablespoons red wine vinegar. Scrape down sides of blender and add 2 cups packed flat-leaf parsley leaves, 4 teaspoon chopped thyme leaves, and 1/2 cup olive oil; blend until just smooth and drizzle over flank steak. Serves 4 to 6.