I forgot to include milk and butter in the ingredient list, but these are all the ingredients you need.
I made egg salad sandwiches this time. Mash up boiled eggs with a spoon, and mix with salt and pepper, mayonnaise and vinegar.
If you add vinegar, you can get by with using less mayonnaise, so I recommend it.
Put the egg salad on one slice of bread, and butter the other slide. Lightly moisten the bread around the edges inside the crust with a finger dipped in milk.
Put the slices together, and cut off the crusts.
Lay plastic wrap on both sides of the sandwich.
Press down tightly on the edges of the bread using the back of a knife, or if that is hard to use, use a ruler.
This version has maple syrup and whipped cream inside.
Carry the sandwich with you in the plastic wrap. Write down what the filling is on the plastic with a marker, if you're planning on enjoying several kinds of pocket sandwiches at the same time.