In a food processor, combine the cheddar cheese, sourdough discard, unsalted butter, all-purpose flour, garlic powder, onion powder, and salt. Pulse until the mixture resembles wet sand, about 30 seconds.

Transfer the dough onto a clean surface and shape it into a disc. Wrap it tightly in plastic wrap and refrigerate for at least 30 minutes, or up to 2 days.

Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper. Roll out the chilled dough to about 1/16-inch thickness and cut into squares.

Lightly sprinkle the cut dough squares with flaky salt for extra flavor. Bake for 18-22 minutes, or until golden brown.

Once baked, allow Sourdough Cheez Its to cool on the baking sheet for about 10 minutes before transferring them to an airtight container.