Step 1: Preheat your oven to 350°F (175°C). Line a large baking sheet with parchment paper.
Step 2: In a medium bowl, combine the sourdough discard, 1/2 cup all-purpose flour, olive oil, and 1/2 teaspoon salt. Mix with a spoon or your hands until a shaggy dough forms.
Step 3: Turn the dough out onto a lightly floured surface. Knead briefly, just for 1-2 minutes, until the dough comes together and is smooth. If adding herbs or cheese, knead them in now.
Step 4: Divide the dough in half. Take one half and place it on a piece of parchment paper. Cover with another piece of parchment paper or plastic wrap. Roll the dough out as thinly as possible using a rolling pin. The thinner you roll it, the crisper your crackers will be.
Step 5: Carefully peel off the top layer of parchment. Transfer the rolled-out dough (still on the bottom parchment) to your prepared baking sheet. Using a pizza cutter or a sharp knife, cut the dough into desired cracker shapes (squares, rectangles, or triangles). Don't separate them yet.
Step 6: Prick each cracker several times with a fork. This prevents them from puffing up too much during baking. Sprinkle generously with extra flaky sea salt or any desired toppings.
Step 7: Bake for 15-20 minutes, or until the crackers are deeply golden brown and crisp. Keep a close eye on them, as they can burn quickly. Baking times will vary depending on oven and thickness.
Step 8: Remove from the oven and let cool completely on the baking sheet. As they cool, they will become even crisper. Once cool, break them apart along the cut lines.
Step 9: Repeat with the second half of the dough. Store cooled crackers in an airtight container for up to a week.