Ingredients

• 1 pound ground turkey breast
• 1 cup vertically sliced Vidalia or other sweet onion
• 4 (1-ounce) slices reduced-fat Swiss cheese
• 4 slices light rye bread
• 1/4 cup part-skim ricotta cheese
• 1/4 cup country-style Dijon mustard
• 1 large egg white
• 1 1/2 teaspoons Worcestershire sauce
• 1 teaspoon olive oil
• 1/2 teaspoon black pepper