Combine the dry ingredients in a food processor or mixer. Mix until everything is well combined.
Cut the butter into small pieces (about 1/2 tablespoon size). Add to the flours. Pulse/mix until the butter is incorporated. The mixture should be a coarse, sandy texture, like cornmeal.
Stir together the honey and 3 tablespoons of the water. With the food processor or mixer running, pour in the honeyed water. Let the it run for a few minutes, allowing the dough to form a ball. The final dough should be soft and a bit wet. If it still has not come together entirely after a few minutes of mixing, add the remaining cold water, a tablespoon at a time.
Put the dough in plastic wrap and put it in the refrigerator for 15 minutes. Preheat oven to 325° F.
Cut the ball of dough in half. Wrap and return the other half to the refrigerator. Put the ball of dough onto the parchment-lined sheet tray. Cover it with the other piece of parchment paper. Carefully, roll out the dough to a rectangle until the dough is about 3/8-inch thick. Cut the dough into 2" squares or rectangles.
Poke the crackers with the tines of a fork. Sprinkle with cinnamon sugar. (Optional.)
Refrigerate the dough for 15 minutes. Repeat 5-7 for other half of dough.
Bake 8 minutes. Turn pan and bake another 8 minutes. (Less for smaller crackers.)
Cool on baking sheet 20-30 minutes. Crackers will continue to harden as they cool.