Preheat the oven to 350°F. Line two baking sheets with parchment paper. Cut two additional pieces of parchment paper for rolling the dough out on.
In a large mixing bowl, combine the melted butter, coconut sugar, and egg. Stir until combined. Add the molasses and vanilla, stir well.
Add the flour, baking soda, sea salt, and cinnamon. Stir until a smooth dough forms. The dough should be soft but not sticky. You should be able to shape the dough into a ball and handle it without it sticking or cumbling.
Lightly dust one of the pieces of parchment paper with additional cassava flour. Place the dough on the parchment paper and flatten it slightly into a rough rectangle shape. Place the other piece of parchment paper on top of the dough and use a rolling pin to roll the dough out into a rectangle.
Roll the dough out to your desired thickness. For thin and crispy graham crackers, the dough should be about 1/8-inch thick. For thicker graham crackers the dough should be about 1/4-inch thick.
Remove the top layer of parchment paper. Use a pizza cutter to slice the dough into rectangles. I cut my graham crackers into 2x3" rectangles. Use a spatula to transfer each graham cracker onto the baking sheet. Repeat the rolling out and cutting process until all the dough has been used up.
Use a sharp knife to score a line across the middle of each graham cracker. Use a fork to make fork pricks above and below the score line on each graham cracker.
Bake the graham crackers for 12-15 minutes. Thinner graham crackers will bake for less time than thicker graham crackers. The graham crackers are done when they are just starting to brown at the corners.
Let the graham crackers cool completely before enjoying or storing in an airtight container.