This is my wife’s tip:
On day hiking trips you probably don’t want to use your regular backpack but still want to carry something more than energy bars and water. Hence the invention of the “smashed sandwich”.
Place two slices of your favorite cheese, cut in half, in the center of a soft burrito. Top with lettuce and thin slices of tomato. Roll up the burrito and wrap it in foil. Place “sandwich” in your hiking bag cramming into the bag as needed. As you hike, the burrito will get softer, the cheese will get warmer and by lunch time you will have a delicious, nutritious smashed sandwich.
(These are quite good).