Preheat the oven to 350 degrees F.
Make the cinnamon sugar. In a small bowl, combine 1 tablespoon cinnamon and the sugar.
In a food processor, combine the whole wheat flour, flour, remaining ½ teaspoon cinnamon, salt, and butter. Pulse until the mix clumps together to form pea-size balls.
Add the vanilla, and ½ cup cold water, 1 tablespoon at a time, until the dough comes together and forms a ball. If the dough feels dry, add 1-2 tablespoons additional water.
Turn the dough out onto a floured surface and form into a ball. Divide the dough in half.
Working with one piece of dough at a time, roll the dough as thin as you can, preferably an ⅛-inch thick (about the thickness of a quarter).
Transfer the dough to a large piece of parchment paper. Brush the dough with melted butter and sprinkle generously with cinnamon sugar, gently pressing the sugar into the dough.
Cut into ½-inch squares. Repeat with the remaining dough.
Carefully transfer the parchment paper to a baking sheet. Separate the squares, spacing them a ½ inch apart.
Bake 12-14 minutes, until golden brown.
Let cool completely, then store in an airtight container for up to 1 week.
