Instructions

• In a bowl combine 1 cup (200 g) mature sourdough starter, 1¼ cups (150 g) semolina rimacinata flour, 2 teaspoons (10 g) extra virgin olive oil, ½ teaspoon fine sea salt, and 1 tablespoon warm water. Mix until the ingredients come together, then knead 3–5 minutes until the dough is smooth and cohesive. If the dough is too dry, add a little more of the warm water, a teaspoon at a time, until the dough is firm but slightly tacky (not sticky). The dough should feel soft, like the skin of your earlobe, unless you used coarser semolina.
• Wrap the dough ball tightly in plastic wrap and refrigerate for at least 30 minutes or up to 24 hours.
• Position a pizza stone on the lower third rack of your oven (or use an upside-down sheet pan that is rated for high temperatures). Preheat the oven to 475°F (245°C) and allow the stone or pan to heat for at least 45 minutes.
• Meanwhile, heat ½ cup filtered or spring water with 1 teaspoon fine salt (not iodized) in the microwave or on the stovetop, stirring until the salt is completely dissolved. Transfer this salt water to a clean spray bottle with a fine mist nozzle, or keep it in a small bowl and use a fine-bristle pastry brush to apply.
• Remove the chilled dough from the refrigerator. Divide it into small balls of approximately 18–20 g each (you should have about 18–20 balls). Drape a piece of plastic wrap over the divided dough to keep the pieces from drying while you work.
• Work with one dough ball at a time. Flatten a ball with your palm and lightly dust both sides with a little semolina flour. Pass the round through a pasta roller, starting at the widest setting and increasing the setting by one notch each pass. Dust with semolina as needed to prevent sticking and rotate the dough a quarter turn between passes so it stays round. Continue until the dough is as thin as your machine will roll it.
• Transfer the pasta-rolled round to a lightly floured surface and roll it even thinner with a rolling pin, using short, firm strokes from the center outward. Continuously move and rotate the dough and dust with semolina as needed. Aim for a super-thin sheet (you should be able to see contrast through it).
• Lightly spritz the top of the thin dough with the prepared salt water (or brush with the salted water).
• Carefully transfer the dough, spritzed side up, onto the preheated pizza stone or hot inverted sheet pan. Bake for about 90 seconds, until the piece puffs and becomes bubbly. Using tongs or a spatula, flip the cracker and bake 1–2 minutes more, until it is crisp and the edges and bubbles are light golden brown while flatter areas remain pale. The cracker is done when it no longer droops when picked up.
• Remove the baked cracker to a cooling rack. Repeat steps 6–9 with the remaining dough, keeping the unused dough balls covered so they do not dry out. If using a spray bottle, shake or agitate occasionally so salt does not settle.
• Once completely cool, store the crackers in an airtight container at room temperature for up to one month.