• Preheat your oven to 325°F. Line 3 large rimmed baking sheets with unbleached parchment paper, and set them aside.

Make the dough.

• In a large bowl, place the superfine white rice flour, potato starch, almond meal and kosher salt, and whisk to combine well. Create a well in the center of the dry ingredients and add the butter, egg white and 6 tablespoons (3 fluid ounces) water, and mix to combine. Add more water by the 1/4-teaspoonful and knead it in with clean hands until the dough holds together well without crumbling. Divide the dough in three roughly equal pieces. Place one on a large piece of parchment paper and cover the other two with plastic wrap.

Roll out the dough and bake the crackers.

• Cover the dough on the parchment with a second piece of parchment paper and roll out into a rough rectangle as close to 1/8-inch thick as possible. Remove the top sheet of parchment paper and cut out rounds with a 1 1/2-inch cookie cutter. Lift the rounds off the parchment with a small offset spatula or flat knife and place, about 1-inch apart, on the prepared baking sheets. Place the baking sheet in the center of the preheated oven and bake until lightly golden brown and dry to the touch (about 12 minutes). Remove from the oven and allow to cool completely on the baking sheet. They will cool quickly. Gather the scraps and press together with one of the remaining pieces of dough. Repeat the process with the remaining dough. The final scraps of dough can be placed on a baking sheet as-is and baked.
• Store the cooled crackers in a sealed glass container at room temperature. They will remain crispy when stored this way for at least a week.