Cube the butter and cream cheese into half inch cubes (more or less.) Put them in the freezer for 20 minutes. Meanwhile, put all the dry ingredients into the food processor. Pulse until all the dries are mixed. Place the cold cheese and butter into the processor and pulse until the mixture forms a mealy texture. Add the buttermilk and process until you have a cohesive ball. It should be wet, but workable. Put dough on a floured surface and, with your hand, pat it into a rectangular shape about 3/4 inch thick. Kneading will make everything tough. Be gentle. Pressing straight down with a knife, cut the dough into 10 - 12 rectangular pieces. Now you have a choice: you can bake them right then and there or freeze them for later. They will keep frozen for perhaps 3 weeks. When you cook, frozen of not, crank the oven up to high (450) and bake 12 - -14 minutes.