Preheat oven and prep baking sheets: Preheat oven to 450 degrees with racks set in the upper and lower thirds of the oven. Line two baking sheets with parchment paper; set aside.
Combine dry ingredients: In a large bowl, whisk together flour, baking powder, sugar, salt, and baking soda.
Transfer half mixture to food processor and add butter: Transfer half of the dry ingredients to the bowl of a food processor. Add butter and pulse until the mixture resembles coarse crumbs, with some larger pieces still remaining.
Mix into remaining dry ingredients; add herbs: Return this mixture back to the bowl with the rest of the dry ingredients. Add herbs, if using, and stir to combine
Add buttermilk and mix: Make a well in the center and gradually add buttermilk, stirring with a fork or wooden spoon until large clumps form; do not allow a dough to form in the bowl.
Knead dough lightly: Turn mixture out onto a lightly floured work surface, and using lightly floured hands, knead two or three times just until a dough forms.
Form into square and cut out biscuits: Pat dough into an 8-by-8-inch square. Using a sharp knife, cut 2-inch square biscuits, or use a 2-inch round cutter.
