Heat oven to 425 degrees. Combine flour, salt, sugar, baking soda, and powder in the bowl of a food processor. Pulse once or twice to combine. Add butter, and process until dough looks like coarse oatmeal. Add buttermilk, and process a few seconds more, until dough just comes together.Advertisement
Turn out dough onto a parchment-lined baking sheet, and pat into a 7-inch circle about 1 inch thick. Using a sharp knife, cut into 8 wedges, but do not separate.
Bake biscuits until golden brown on top and firm, about 20 to 25 minutes. Serve warm with butter.