Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper or silicone baking mat and set aside.
In a large mixing bowl, whisk together the gluten-free flour, baking powder, dark brown sugar, and salt until well combined.
Add the room temperature butter to the dry ingredients. Using a pastry cutter or your fingers, work the butter into the flour mixture until it resembles coarse crumbs.
Add the milk and honey into the dry ingredients. Stir until a dough forms. If the dough seems too dry, you can add a little more milk, one tablespoon at a time, until it comes together.
Transfer the dough onto a lightly floured surface and knead it gently until smooth. Divide the dough in half.
Roll out one portion of the dough between two sheets of parchment paper until it's about ⅛ inch thick. Use a knife or a pizza cutter to trim the edges and cut the dough into rectangles or squares, as desired.
Transfer the cut-out dough shapes onto the prepared baking sheet, leaving a little space between each cracker.
Use a fork to prick the surface of each cracker a few times to prevent them from puffing up too much during baking.
Repeat the process with the remaining dough until it's all used up.
Bake the crackers in the preheated oven for 12-15 minutes, or until they are golden brown around the edges.
Remove the baking sheet from the oven and let the crackers cool completely on the pan.
Once cooled, break the crackers apart along the scored lines.
Store the gluten-free graham crackers in an airtight container at room temperature for up to one week.