Grilled Cheddar-Chicken Fillet Sandwiches Recipe - BettyCrocker.com

Ingredients

• 4 boneless skinless chicken breasts (about 1 1/4 lb)
• 1/2 teaspoon seasoned salt
• 1/4 teaspoon coarse pepper
• 1 medium Bermuda or other sweet onion, sliced
• 4 oz fresh mushrooms, cut in half (1 1/2 cups)
• 1 tablespoon olive or vegetable oil
• 3 tablespoons creamy mustard-mayonnaise sauce
• 4 slices sourdough bread (about 3/4 inch thick)
• 4 slices (3/4 oz each) sharp Cheddar cheese