Whole Wheat Crackers

I made these a couple days ago and we have been loving them.  They are found on page 518 of Nourishing Traditions.
 2 1/2 cups whole wheat flour or spelt or kamut
1 cup plain yogurt
1 t salt
1 1/2 t baking powder
2 T sesame seeds, toasted in the oven ( I did not have sesame seeds (until today when I got a surprise package from mom) so I used flax seed)
8 T butter

Mix flour with yogurt and let it soak for 24 hours.  Mix soaked four, salt, baking powder, and 4 T butter.  Then add sesame seeds.  Roll out 1/8 inch thick.  She then cuts it into squares and puts it on a buttered cookie sheet.  I put it in a dehydrator.  I buttered 3 racks and spread them throughout.  I would cook them for like 16 hours on medium heat.