1. Preheat your oven to 350 F (175 C). Line two large baking sheets with parchment paper.

2. In a medium-sized bowl, whisk together the sourdough discard, olive oil, salt, garlic powder, and black pepper until well combined and smooth.

3. Gradually add the all-purpose flour and 1/2 cup of grated Parmesan cheese to the wet mixture. Stir with a spatula or wooden spoon until a shaggy dough forms.

4. Use your hands to gently knead the dough within the bowl for about 1-2 minutes until it comes together into a cohesive ball. It should be soft and slightly tacky. If too sticky, add a tiny bit more flour, a teaspoon at a time.

5. Divide the dough in half. On one of the prepared baking sheets, place one half of the dough. Cover it with another piece of parchment paper or plastic wrap and roll it out very thinly, to about 1/16 to 1/8 inch thick. Repeat with the second half of the dough on the other baking sheet.

6. Remove the top layer of parchment paper. Using a pizza cutter or a sharp knife, score the dough into desired cracker shapes (squares, rectangles, or triangles). Do not separate them yet. Sprinkle generously with extra grated Parmesan cheese and, if using, a pinch of flaky sea salt.

7. Transfer the baking sheets to the preheated oven. Bake for 15-20 minutes, or until the crackers are golden brown and crisp. Keep a close eye on them, as baking times can vary.

8. Once baked, remove the baking sheets from the oven. Let the crackers cool completely on the baking sheets. As they cool, they will crisp up further. Once cool, break them apart along the scored lines.