1 baguette, halved crosswise and split open (leaving hinge intact)
1 small clove garlic
1tbsp. mayonnaise
2tsp. Dijon mustard
2tsp. anchovy paste
4oz. romaine heart, leaves separated
2 ribs celery, very thinly sliced
1oz. Parmesan cheese, grated (1/4 cup)
2 Roma tomatoes, sliced
Instructions
Step 1Heat grill to medium.
Step 2Rub chicken with 1/2 teaspoon olive oil and sprinkle with 1/4 teaspoon each salt and pepper. Grill until instant-read thermometer registers 165°F, 8 to 10 minutes per side. Transfer to cutting board and let rest 10 minutes before slicing.
Step 3While chicken is grilling, grill lemon halves and baguette, cut sides down, until charred, 2 to 3 minutes. Transfer to cutting board. Rub cut side of baguette with garlic clove.
Step 4Squeeze 2 tablespoons juice from grilled lemon halves into small bowl and whisk in mayonnaise, Dijon, and anchovy paste, then gradually whisk in remaining 2 tablespoons oil until thoroughly incorporated.
Step 5In large bowl, toss romaine and celery with 1/4 cup dressing and 1/4 teaspoon pepper to coat, then toss with Parmesan and another 1/4 teaspoon pepper.
Step 6Drizzle remaining dressing on baguette and layer with sliced chicken, salad, and tomatoes. Cut each in half to make 4 sandwiches.