Ingredients

• 1 onion, chopped
• 3 tablespoons vegetable oil
• 1 teaspoon salt
• 1 pinch ground black pepper
• 1/4 teaspoon dried tarragon
• 1 cup chicken broth
• 3 tablespoons all-purpose flour
• 1/2 cup milk
• 2 cups diced, cooked chicken meat
• 1 egg yolk, beaten
• 1 tablespoon lemon juice
• 1/4 cup sherry
• 1 red bell pepper, chopped
• 1 avocado - peeled, pitted and diced
• 6 slices toasted white bread