For Hers: To make the sandwich, spread the mayonnaise on 2 slices of bread. Top 1 slice of bread with 1 slice of meatloaf, 1 slice of tomato and the cole slaw. Top with the other slice of bread.
For His: To make the sandwich, spread the mustard on the remaining 2 slices of bread. Top 1 slice with the remaining slice of meatloaf, tomato and the lettuce. Top with the other slice of bread.
Preheat the oven to 350 degrees F.
Heat 1 tablespoon oil in a small skillet over medium-low heat until hot but not smoking. Add the chopped onion and saute until softened and brown, about 6 minutes. Add the parsley and cook for another minute. Set aside.
In a large mixing bowl, combine the turkey with the breadcrumbs, egg, 1/4 cup of the ketchup, cooked onion mixture, salt and pepper. Mix until fully combined. Form into a loaf and transfer to a 9-by-5-inch loaf pan. Using a pastry brush or the back of a spoon, brush the remaining 3 tablespoons of ketchup over the loaf.
Evenly scatter the sliced onions over the loaf, drizzle with the remaining tablespoon of oil and sprinkle with salt and pepper. Bake until the meatloaf is cooked through, 55 to 60 minutes. Yield: 4 to 6 servings
In a large bowl, combine the cabbage, onion, mayonnaise, relish, lemon juice, Dijon-mayonnaise spread and salt and pepper to taste. Chill for at least 30 minutes and up to overnight before serving.