Step 1 In a food processor fitted with the steel blade or in the bowl of an electric mixer fitted with the paddle attachment, combine the flour, brown sugar, baking soda and salt. Pulse or process on low to mix. Add the butter and pulse on and off, or mix on low, until the mixture is the consistency of coarse meal.
Step 2 In a small bowl, whisk together the honey, milk and vanilla. Add to the flour mixture and pulse on and off a few times or mix on low until the dough barely comes together. It will be very soft and sticky.
Step 3Turn the dough out onto a lightly floured work surface and pat it into a rectangle about 1 inch thick. Wrap in plastic and chill until firm, about 2 hours or overnight.
Step 4Divide the chilled dough in half and return one half to the refrigerator. Sift an even layer of flour onto the work surface and roll the dough into a long rectangle about one-eighth inch thick. The dough will be sticky, so flour as necessary.
Step 5Trim the rectangle to 4 inches wide. Cut the strip crosswise every 4 1/2 inches to make 4 crackers. Gather the scraps together and set aside. Place the crackers on one or two parchment-lined baking sheets and sprinkle with the sugar-cinnamon mixture. Chill until firm, about 30 to 45 minutes. Repeat with the second batch of dough.
Step 6Adjust the oven racks to the upper- and lower-third positions and heat the oven to 350 degrees.
Step 7Gather the scraps together into a ball, chill until firm and reroll. Dust the surface with more flour and roll out the dough to get two or three more crackers.
Step 8Mark a vertical line down the middle of each cracker, being careful not to cut through the dough. Using a toothpick or skewer, prick the dough to form two dotted rows about one-half inch from each side of the middle dividing line.
Step 9Bake for 20 to 25 minutes, until browned and slightly firm to the touch, rotating the baking sheets halfway through to ensure even baking. Makes about 10 large crackers.