In a mixing bowl, combine the flour, salt, sourdough starter, melted butter, herbs, sesame and, of course, the any improvised spice. Knead them together until a smooth and non-sticky dough forms. You might be tempted to sneak a taste here.
Divide the dough in half and shape each portion into a small rectangular slab. Cover both halves with plastic wrap and let them chill in the fridge for at least 30 minutes (or up to a couple of hours) until they become firm.
Preheat your oven to 350°F (180°C). Very lightly flour a piece of parchment, your rolling pin, and the top of the dough. Working with one half at a time, roll the dough out until it's about 1/16" thick. Try to make it as even as possible. Admire the marbled patterns created by the hidden ingredients.
Transfer the rolled-out dough with parchment onto a baking sheet. Now, lightly brush with olive oil and sprinkle salt over the top. This is where the magic really happens – the aroma of herbs, sesame, and herbs melds together. Cut the dough into 1 1/4" squares, and use a rolling pizza wheel for precise results. Don't forget to prick each square with the tines of a fork for that classic cracker appearance.
Bake the crackers for 20 to 25 minutes until they start to brown around the edges. Rotate the baking sheets halfway through to ensure even browning. When fully golden browned and perfectly crispy, take the crackers out of the oven. Transfer your Surprise Herb Sourdough Crackers with a Twist to a cooling rack. They're ready to share, savor, and surprise your taste buds.