Preheat your oven to 350°F. Line a rimmed baking sheet with unbleached parchment paper, and set it aside.

In a large bowl, place the all purpose flour, xanthan gum, sorghum flour, teff flour, sugar, baking powder, baking soda and salt, and whisk to combine well.

Add the melted butter and milk, and mix to combine until the dough begins to come together. Knead the dough until it’s smooth. Divide the dough into two parts, and press each into a small ball.

Place the first ball of dough on a clean surface and sprinkle with 1 to 2 tablespoons of flour.

Knead the dough to incorporate the flour and smooth out the dough. Using a rolling pin, roll the dough into a rectangle about 1/8-inch thick (about the thickness of a nickel).

The dough should roll out quickly and easily. With a pastry wheel or sharp knife or a 1-inch square cookie cutter, slice the dough into 1-inch square crackers.

Place the squares them on the prepared baking sheet, less than 1-inch apart (they will not spread during baking).

Gather the scraps, add to the other half of the dough and repeat the process until you’ve used all the dough. Sprinkle the tops of the rounds liberally with kosher salt.

Place the baking sheet in the center of the preheated oven and bake, rotating once during baking, for 9 to 12 minutes, or until the crackers are golden brown around the edges. Allow to cool completely on the baking sheet. Store in a tightly sealed glass container at room temperature.