Don’t chip a tooth.
Hardtack has been used for a couple hundred years as a food for those who are under rough field conditions, such as sailors on wind-powered ships or soldiers in the field. British lexicon uses the work “tack” as food, so “hardtack” is just “hard food.” Hardtack is a literal “forever food.” Hundred-year-old hardtack remains eatable and has the original nutrition as when it was created.
This is very easy to make with three components, flour, water and salt. You can scale it up the batch size as far as you want to, just not too far. 1 cup flour, 1 cup water and a teaspoon of salt. The salt is on a “sliding scale.” If you’re doing 3-4 cups worth, make it two teaspoons of salt.
Adding any kind of taste to it like Oregano or honey to the mix will improve the taste slightly, however it will also shorten the shelf-life. The good news is we’re talking from “forever” to 5-10 years.
Start with the flour, salt and half the water. Commence mixing. Slowly add the remaining water while mixing until you have a dough, then spread it out to about 1/8” thick. Cut it into shapes and ventilate it with holes to prevent rising make sure the interior gets dry and to help with breaking it into pieces later.
You need to now bake it until it is totally dry. You can do this with high heat (350 degrees) for a short time (30 minutes, flip and 30 more) or low heat (175 degrees) for a longer time (1 hour, flip, 1 hour). Once cooled, store in cool, dry place in something like a Mason jar, plastic bag or the like.
Now, having is not the same as eating. Hardtack is called “hard” for a reason. It is almost building-grade brick hard. To try and eat this “as-is” will not be easy. The recommended way to eat this is to break it into small pieces (that’s one of the reasons the holes are in it for, stress points to make breaking them up easier) and soak them in water to soften it, then add to soups or fry them in grease to make them eatable and hopefully semi-palatable. Tasteless is a feature, not a bug. There might be bugs in it if you don’t store it properly.
You can survive on this as our forefathers did. It’s no “Fluffy Chocolate Brioche with Raspberry Jam” but it will keep you fed. I would say “Enjoy!” but I know you won’t.