I found this recipe in my old backpacking recipies. Never tried it, but sounds better than the store bought ones. Looks like a winter afternoon's project.

Hardtack Recipe:

3 cups all-purpose flour 1 cup whole wheat flour 1/2 cup yellow cornmeal 1/2` cup cracked wheat 1 tablespoon sugar 1 tablespoon salt 1 3/4 cups buttermilk

Combine flours, cornmeal, wheat, sugar and salt. Add buttermilk, mix well, and knead briefly. Shape dough into golf-ball-sized portions. Dust with flour and roll very thin. Place on greased and floured baking sheet. Bake at 400 degrees, turning several times, until lightly browned on both sides. Cool; then store in waterproof container. Keep from moisture. This makes about twenty four 3 1/2 inch crackers. My last batch took about 24 minutes, turning 4 times for each of the two oven loads.