Preheat: Preheat your oven to 175℃ (350℉).
Combine the dry ingredients: In a medium bowl, mix the flour, rosemary and sea salt.
Combine wet ingredients: In a separate bowl, mix the sourdough discard, melted butter and olive oil.
Form the dough: Pour the wet ingredients into the dry ingredients. Stir with a spatula or Danish Wisk until a shaggy dough forms. If it really is too dry to hold together, add half a tablespoon of water at a time until it is in a ball. Do not overmix.
Roll out: Turn the dough out onto parchment paper. Using your rolling pin, roll it out as thin as you possible can (2mm). The thinner the crispier your crackers will be.
Score and season: Use a pizza cutter or sharp knife to score crackers into rows in the size cracker you desire. Use a fork and lightly push holes in each cracker. For extra taste, drizzle lightly with olive oil and a sprinkling of sea salt.
Bake: Transfer your parchment paper and crackers onto an oven tray. Bake for 20 minutes, keeping a close eye on them so they do not burn. Look for deeply golden brown edges.
Cool: Let them cool before breaking up and serving. Enjoy!