Preheat your oven to 375°F (190°C). In a large bowl, add the melted butter, sourdough starter discard, all-purpose flour and salt. Use a spatula to stir until the ingredients are combined. The dough should be soft and pliable. It should not stick to your fingers. If the dough seems too sticky, mix in an additional 20 grams of flour.

Cover the bowl and let the dough to rest for 20-30 minutes for the flour to absorb the liquid. (or in the fridge for up to 2 days wrapped in plastic wrap for a long fermented cracker.)

Place the dough between two pieces of parchment paper. Use a rolling pin to roll the dough out to a 1/16th inch thickness. Cut the dough into rectangles using a sharp knife. (You can also use bench-scraper or pizza cutter.)

Prick each rectangle a few times with a fork. (This will keep the crackers from puffing up as they bake.)

Bake the crackers for 15-17 minutes, checking to make sure they do not over-brown. Allow the crackers to cool before breaking them apart. They will continue to become more crisp as they cool. Store in an airtight container.