Mix all ingredients together to make a batter that does not stick to your hands, as dry as possible.
Roll out or press onto an non-greased cookie sheet to a thickness of ½ inch thick. Bake for 30-45 minutes.
Remove from oven and cut into 3-inch squares. Punch 4 holes into each cracker. Do not pierce all the way through. Flip and bake for another half hour or until crackers are dry. Turn oven off and leave hardtack in the oven until they are cool.
Note: Cooking times may vary. Hard tack can keep for up to a year.