Directions

1. Put the flour, cornstarch, sugar, yeast, baking powder, and 1 teaspoon of the Flower Salt into a mixing bowl. Whisk gently to combine these ingredients and set the bowl aside.

2. Put the buttermilk and butter into a microwave-safe bowl or cup.
3. Microwave on until butter has mostly melted and milk is warm, about 45 seconds. Stir until the butter has completely melted and the milk has cooled slightly. Test a drop of the milk on your wrist – it should be just warmer than body temperature. Alternatively, warm the buttermilk and butter in a small saucepan set over medium heat.
4. Add the buttermilk mixture all at once to the flour mixture. Use a spatula
5. to stir until most of the flour has been incorporated into a shaggy dough. Use your hand to incorporate the remaining flour into the dough. Cover the bowl tightly and set in a warm spot for 15 minutes.
6. Uncover the bowl and, using slightly wet fingers, pinch the edge of the dough and pull that bit, stretching it up and over to the center-top of the dough. Repeat this action, moving around the edge of the dough (about six times). Cover the bowl and again set it in a warm spot for 15 minutes.
7. Prepare two rimmed baking sheets by setting a cooling rack into each of them. Set aside.
8. Cut the dough in half using a spatula or bowl scraper. Scatter flour generously on a work top. Shape one half of the dough into a ball and roll it out, turning it and adding flour to the work top as needed, until very thin, about 1/16-inch.
9. Lightly brush the top of the rolled dough with oil. Use a pizza cutter or sharp knife to cut the dough into strips, then ‘squares.’ Poke the top of each square once or twice with the tines of a fork. Use a thin spatula to transfer the squares to the rack in one baking sheet. Repeat with the remaining half of the dough and the other baking sheet. Sprinkle the remaining Flower Salt over the dough squares.
10. Preheat the oven to 375° F. Let the dough squares rest as the oven comes up to temperature, 15-20 minutes.
11. Transfer the baking sheets to the oven and bake for 10 minutes. Reduce the oven setting to 350° F, open the oven door briefly (to release steam), and bake until the squares are lightly golden and crisp, an additional 15-20 minutes. If the crackers aren’t fully dry/crisp, leave them in the oven, turn the oven off, and crack the oven door open. Check on them again after 10 minutes.