In a food processor fitted with a dough blade, combine the shredded cheese, all-purpose flour, onion powder, garlic powder, salt, room-temperature unsalted butter, and sourdough discard. Process until a soft dough forms. If the dough isn't coming together after a minute, add 15 grams (1 tablespoon) of cold water.

Alternatively, you can mix the ingredients by hand using a mixing bowl and a pastry cutter. If you prefer, you can also use an active sourdough starter, ensuring to use the same weight in grams.

Once the dough has formed into a ball, take it out of the food processor and divide it into two equal pieces. Shape each piece into a flat disc and wrap them in plastic wrap. Chill in the refrigerator for at least 1 hour. If you want to ferment longer, you can store the dough in the fridge for up to 2 days.

When you're ready to bake, preheat your oven to 350 degrees F (175 degrees C) and line a large baking sheet with parchment paper.

Let the dough rest at room temperature for 20 minutes to make rolling easier. On a lightly floured surface, roll out the dough into a large rectangle about ⅛ inch thick.

Use a goldfish-shaped cutter, or a pizza cutter, sharp knife, or small cookie cutter to cut the dough into your desired shapes. Make sure the crackers are similar in size for even baking. Continue re-rolling the remaining dough until all crackers are cut.

Gently pop the goldfish shapes out of the cutter and place them on the prepared baking sheet. If you like, use a toothpick to poke an eye and the edge of a spoon to create a mouth on each cracker.

Sprinkle the crackers with flaky sea salt and bake for 15-20 minutes, or until they turn golden brown.

Once baked, remove the crackers from the oven and let them cool slightly on a wire rack. Enjoy your homemade goldfish crackers!