Hardtack
Preservation of food was a constant struggle for those pushing the frontiers of the new America, as well as for those on the coastal colonies. If you were part of the army, then you had even more need for food that wouldn’t go off, even if you were marching for weeks with no access to fresh provisions.
Hardtack was a popular food for colonial soldiers, but it had been around for centuries in different forms by this point. It is essentially a cross between a thick, tough cracker and a loaf of unleavened bread. Being flat, it was easy to pack, and it took forever to go off, meaning soldiers could munch on it when on long journeys.