In a large mixing bowl, combine sourdough discard, both flours, melted butter, and table salt.

Stir until well combined. If dough is very sticky, add a bit more flour until it is manageable.

Divide dough into two pieces and form each into a disk. Wrap each half in plastic wrap and chill for at least 30 minutes.

Preheat oven to 375F (190C) and line two baking sheets with parchment paper. Set aside.

Remove one disk of dough from refrigerator and unwrap.

Place on a lightly floured surface and use a rolling pin to roll dough to be under ⅛” thick (<3mm). While rolling, occasionally use a spatula to scrape under the dough to keep it from sticking too much to your countertop. Transfer sheet to prepared baking sheet and use a fork to pierce dough all over (to help prevent bubbles).

Lightly brush all over with olive oil, then use a pizza wheel or pastry cutter to cut into 2” squares (no need to separate the crackers).

Sprinkle liberally with kosher salt. Transfer to center rack of 375F (190C) oven and bake until light golden brown, about 20 minutes.

Repeat steps 5-8 with second disk of dough.