1. Heat the oven to 375 degrees . In a large bowl, whisk together the flours, sugar, table salt, sesame seeds, and herbs. Use a fork or your fingers to work in the softened butter until its evenly blended.
2. Make a well in the dry ingredients. Add all the milk and stir until a dough begins to form. Turn the dough out onto a lightly floured work surface and gently knead it until its smooth. Add more milk, 1 teaspoon at a time, if the dough is dry.
3. Flatten the dough into a disk and halve it. Sprinkle your work surface with more flour and shape one of the halves of dough into a rectangle. Roll it out into a thin rectangle, about 9 by 16 inches. Carefully transfer it to a rimmed, parchment lined baking sheet.
4. Brush the dough with water, scatter on sesame seeds and herbs, and sprinkle lightly with kosher salt. Use a pizza cutter or a butter knife to cut the dough into 12 or more same-size pieces. Don'tseparate the pieces or trim off the rough edges.
5. Bake the dough until its just golden brown, about 15 minutes, turning the pan at least once halfway through. (Keep watch as it bakes; you may need to turn the pan more than once for even browning.) Transfer the pan to a cooling rack and let the crackers cool completely, then break them along the cut lines. Repeat with the remaining dough. The crackers can be stored in an airtight container at room temperature for three days.