Preheat oven to 350 degrees.
With a mortar and pestle, crush the rosemary and coarse salt together for topping. Put topping ingredients in a small bowl. Stir in the one teaspoon of parmesan cheese (if using cheese). Set aside.
Stir, in a medium bowl, the sourdough starter, almond flour, olive oil, butter, salt, parmesan cheese (if using), and herbs.
On two parchment lined stone bar pans or cookie sheets, divide the dough between the two pans, and spread until very thin and even on both trays.
Using a spatula dipped in a small amount of water, or your fingers dipped in water, smooth the top of the cracker dough. Then sprinkle with the topping ingredients, reserving enough for the second pan. Repeat for second pan.
Bake one pan at a time on the middle rack, or if baking both trays at the same time, rotate after 10 minutes.
Remove from oven and score with a sharp knife (making straight lines for your cracker squares). You do not need to push the knife through to the bottom of the pan. This scoring will help you break these into nice square crackers once cooled.
After scoring the dough, reduce the oven temp to 325 and return each tray to the oven for 15-20 minutes (rotating between racks again after another 10 minutes) or until the crackers are golden brown on the edges. If some crackers are browning more than others, remove the done ones and return pan to oven to finish baking.
Remove from oven. Cool completely before breaking on the scored marks and and moving to an airtight container (whatever is left after you enjoy some!)