Caesar Chicken Burgers Recipe | Say Mmm

Ingredients

• 4 boneless skinless chicken breast halves (4 ounces each)
• 1/4 teaspoon salt
• 1/4 teaspoon pepper
• 4 slices red onion
• 2 tablespoons butter, softened
• 4 hamburger buns, split
• 2 cups torn romaine
• 1 tablespoon grated Parmesan cheese
• 1/2 cup creamy Caesar salad dressing, divided