In a medium bowl, combine cake flour, instant yeast, baking soda, cream of tartar, and sugar. Whisk together until fully blended.

In a small saucepan, gently heat the butter, vegetable oil, and water until the butter melts completely. Cool this mixture to around 120°F.

Create a well in the dry ingredients and pour in the warm butter mixture. Using an electric mixer, blend on medium speed, then increase to high until the dough begins to form.

Transfer the dough to a lightly floured surface and knead by hand until it forms a soft, smooth ball. Add more flour if it's sticky or a little water if too dry.

Lightly grease a mixing bowl, place the dough inside, and cover with plastic wrap. Refrigerate for 12 to 18 hours.

Once the dough is ready, remove it from the refrigerator and let it rest at room temperature for 15 minutes. Preheat your oven to 400°F.

Knead the rested dough for a few minutes, then divide into four portions and roll each piece as thin as possible.

Cut the rolled dough into 2x2-inch squares, arranging them closely on a prepared baking sheet.

Prick each cracker with a fork and brush the tops with water, then sprinkle with sea salt or herbs before baking.

Bake the crackers for 8 to 10 minutes, monitoring closely after 8 minutes to avoid excessive browning.

Once baked, allow the crackers to cool on the baking sheet before transferring to an airtight container.