Preparation Combine the mayonnaise, yogurt, lemon zest and juice. Set aside. Toast the bread. To assemble the sandwiches, place the bread on a work surface and spread with the lemony sauce. Top with 1 leaf of lettuce (fold it if necessary), 1 slice of tomato, 1 slice of onion, one-fourth of the kipper filets and 1 ounce/28 grams of the avocado. Season with freshly ground black pepper. Tina's Tip:Kippers on toast is a classic meal in Great Britain and Ireland, while sardines are more popular in Scandinavia. Either fish works in this recipe, and if you have leftovers, toss them into eggs, a salad or a red sauce for a punch of flavor!Per Sandwich: Calories 380, protein 17 g, total fat 19 g, carbohydrates 37 g, sodium 690 mg, fiber 12 g Nutritional analysis provided by The Truly Healthy Family Cookbook Reprinted with permission from The Truly Healthy Family Cookbook: Mega-nutritious Meals that are Inspired, Delicious and Fad-free by Tina Ruggiero, M.S., R.D., photography by Bill Bettencourt. Copyright © 2013 Tina Ruggiero. First published in 2013 by Page Street Publishing.