Sourdough Crackers

1 cup Flour
1/2 teaspoon salt
1 cup unfed ("discarded") sourdough starter
1/4 cup (4 tablespoons) butter, room temperature
2 tablespoons dried herbs of your choice, optional
oil for brushing
coarse salt for sprinkling on top

Mix together the flour, salt, sourdough starter, butter, and optional herbs to make a smooth (not sticky), cohesive dough.
Divide the dough in half, and shape each half into a small rectangular slab. Cover with plastic wrap, and refrigerate for 30 minutes, or up to a couple of hours, until the dough is firm.
Preheat the oven to 400°F.
Very lightly flour a piece of parchment, your rolling pin, and the top of the dough.
Working with one piece at a time, roll the dough to about 1/16" thick. The dough will have ragged, uneven edges; that's OK. Just try to make it as even as possible.
Transfer the dough and parchment together onto a baking sheet. Lightly brush with oil and then sprinkle the salt over the top of the crackers.
Cut the dough into 1 1/4" squares; a rolling pizza wheel works well here.
Prick each square with the tines of a fork.
Bake the crackers for about 20 minutes, until the squares are starting to brown around the edges.
When fully browned, remove the crackers from the oven, and transfer them to a cooling rack. Store airtight at room temperature for up to a week; freeze for longer storage.
Yield: about 100 crackers, 20 servings.