-
Preheat the oven to 400°F. Get out two large baking sheets; there's no need to grease them. If you have parchment, get out two pieces of parchment.
-
Whisk together the dry ingredients, then work in the butter until the mixture is crumbly.
-
Add the grated cheese and stir until thoroughly combined.
-
In a separate bowl whisk together the egg and vinegar until frothy, then add the water.
-
Add the wet ingredients all at once to the dry ingredients, mixing to make a cohesive dough. Add additional water a teaspoon at a time, if necessary to bring the dough together.
-
Divide the dough into two pieces, and shape each into a rough square.
-
Roll out one piece of dough at a time, keeping the piece you're not working with covered to prevent drying.
-
Lightly dust your work surface, or a piece of parchment, with gluten-free flour blend.
-
Roll the dough 1/4" thick, and cut into 1" squares, use a pizza or pastry wheel, a bench knife, or a plain knife. Prick each cracker with a fork.
-
If you've rolled on parchment, simply lift the parchment onto the baking sheet. Separate the crackers a bit, leaving about 1/4" between them, so they crisp evenly. If you're not using parchment, transfer the crackers to the baking sheet, leaving about 1/4" between them.
-
Repeat with the remaining piece of dough.
-
Bake the crackers for 12 to 16 minutes, until their edges are starting to brown.
-
Remove them from the oven, and cool right on the pan.
-
Store cooled crackers in an airtight container, or tightly wrapped in plastic.