1 cup of all purpose flour (my choice is whole wheat) You can substitute Gluten free flours and try your hand at that.
A couple of tablespoons of butter
6-8 tablespoons of water
1/2 teaspoon of salt
Now, you see, a simple list of ingredients. Mix them up in a blender in the following manner: Flour, butter and add water till a ball of dough forms. When you can lift it out without it being stringy, put it on a cutting board and roll it out to about an 8th of an inch in thickness (your discretion and experimentation). Place it on a cookie sheet and bake for 10 to 15 minutes ( watching it at 10 minutes and decide how brown you want it.) If you didn't score it before baking, break it up into sizes that you would enjoy!
That simple. Here is a Youtube Video of another way!