In the bowl of a stand mixer fitted with the paddle attachment, combine the softened unsalted butter and firmly packed light brown sugar. Beat at medium speed until creamy, about 3 to 4 minutes, stopping once or twice to scrape down the sides and bottom of the bowl.

Add the molasses and vanilla extract to the butter mixture and beat on low speed until fully incorporated.

In a medium bowl, whisk together the all-purpose flour (1 3/4 cups), whole wheat flour (1 cup), ground cinnamon, baking soda, and kosher salt until evenly mixed.

With the mixer on low speed, add the flour mixture to the butter mixture gradually, mixing just until no large streaks of flour remain and the dough comes together.

Turn the dough out onto a lightly floured work surface. Shape it into a rough rectangle, flatten slightly, wrap tightly in plastic wrap, and refrigerate for 1 hour.

When the dough has chilled for 1 hour, preheat the oven to 350°F (180°C) and line baking sheets with parchment paper.

Heavily dust the work surface and a rolling pin with all-purpose flour. Unwrap the dough and roll it to an even 1/4-inch thickness.

Dip a 2 1/4-inch fluted square cutter in flour, then cut shapes from the rolled dough. Transfer the cut crackers to the prepared baking sheets, spacing them about 2 inches apart. Reroll scraps as needed and continue cutting until all dough is used.

Lightly sprinkle the tops of the cut crackers with turbinado sugar.

Bake the crackers on the prepared sheets until the edges are golden brown and the centers are set, about 17 to 20 minutes.

Let the crackers cool on the baking sheets for 5 minutes, then transfer them to wire racks to cool completely.

Store cooled crackers in an airtight container for up to 1 week.