Preheat the oven to 375°F (190°C). In a food processor, add the gluten-free flour blend, xanthan gum (if your blend doesn’t already contain it), brown sugar, ground cinnamon, baking powder, baking soda, and salt. Pulse until the mixture is blended.
Place the cold butter into the flour mixture.
Pulse the food processor about 10-15 times, until the butter is in small pieces, the largest being about the size of a pea.
Add the honey, molasses, whole milk and vanilla extract to the food processor.
Blend until a dough is formed.
Place the dough on a piece of parchment paper the size of a half sheet pan, 11x15-inches large. Place another piece of parchment paper on top of the dough.
Roll out the graham cracker dough until it’s a rectangle the size of the parchment sheet and rolled to ⅛ to ¼ of an inch thick. Peel back the top sheet of parchment paper.
With a pizza cutter or knife, cut the dough into squares, about 2.5 x 2.5 inches in size. I use a ruler to mark off every 2.5 inches on the dough. You’ll get 24 squares total.
Use a fork or skewer to poke rows of holes in each square.
Slide the parchment paper with the dough on it onto the baking sheet. Refrigerate for 30 minutes to chill the dough.
Bake at 375°F (190°C) for 15-17 minutes, until the edges are slightly brown and crispy, and the top of the graham crackers no longer looks shiny.
Place the pan on a cooling rack and immediately reinforce the score lines by slicing through them again with a pizza cutter or knife. Let cool completely to crisp up.