Mix together all ingredients except milk, water, and sesame seeds, using a pastry cutter or fork. Add milk to make a dough the consistency of pie crust. Freeze dough overnight. Cut in half while still frozen, and after about half an hour roll out and cut into desired cracker shapes. Place crackers on a greased cookie sheet and prick with a fork. Brush lightly with water and sprinkle with sesame seeds if desired. Bake at 350 degrees F for 8 to 10 minutes. Store in a covered container or in the freezer. Warm briefly in the oven to crisp the crackers.