Now you can eat like a 19th-century soldier or sailor (or cowboy!). Just mix up this recipe and then serve it with, respectively, coffee, rum, or beans. Ration of semi-rancid meat sold separately.
To make hardtack: Mix 2 cups all-purpose flour, 2 cups whole wheat flour, and 1 tsp salt. Form it into a dough using 1.5 cups of water.
Let the dough rest for 10 minutes. Then spread it into a pan, prick it all over on top with a fork, and bake it for 50 minutes at 325 degrees F.
Hardtack recipe comes from The Food Journal of Lewis & Clark: Recipes for an Expedition
by Mary Gunderson. The other recipes in this book are a lot more appetizing.
Image: Infrogmation of New Orleans, via CC license. Why Mr. T. T. Wentworth Jr. decided to preserve a piece of hardtack from 1862, I have no idea. People collect weird things.