In the bowl of a stand mixer fitted with the paddle attachment, beat butter and brown sugar at medium speed until creamy, 3 to 4 minutes, stopping to scrape sides of bowl. Beat in molasses and vanilla.

In a medium bowl, whisk together flours, cinnamon, baking soda, and salt. With mixer on low speed, gradually add flour mixture to butter mixture, beating until combined. Turn out dough onto a work surface, and shape into a rectangle. Wrap in plastic wrap, and refrigerate for 1 hour.

Preheat oven to 350°F (180°C). Line baking sheets with parchment paper.

Heavily dust work surface with all-purpose flour; on prepared surface, roll dough to ¼-inch thickness. Using a 2¼-inch fluted square cutter dipped in all-purpose flour, cut dough, and place 2 inches apart on prepared pans with 2 dough pieces touching each other to create a sheet. Reroll scraps, and cut to use all dough. Sprinkle with turbinado sugar.

Bake until edges are golden brown and centers are set, 17 to 20 minutes. Let cool on pans for 5 minutes. Remove from pans, and let cool completely on wire racks. Store in an airtight container for up to 1 week.