Coronation Chicken Salad Sandwiches

Name: Coronation Chicken Salad Sandwiches
Ingredients: 1 tablespoon salted butter; 1 cup chopped yellow onion; 6 tablespoons Major Grey’s chutney*; ¼ cup tomato puree; ¼ cup water; 2 tablespoons red wine vinegar; 2 tablespoons curry powder; 1 tablespoon fresh lemon juice; ½ teaspoon salt; ¼ teaspoon ground black pepper; 1 bay leaf; ½ cup mayonnaise; 3 cups finely chopped roast chicken; ½ cup chopped toasted slivered almonds; 3 tablespoons finely chopped dried apricots; 2 tablespoons finely chopped green onion (green tops only); 2 tablespoons finely chopped parsley; 2 tablespoons dried currants; 12 slices potato bread