Preheat the oven to 375° F.
In a large bowl, sift together the flour, sugar, baking powder, and salt. Work the butter into the flour with a pastry cutter or your fingertips, until it resembles coarse meal. Pour in the buttermilk and mix with a fork until the buttermilk has just been incorporated. Gently knead the dough, in the bowl, a few times to bring the dough together. Divide the dough into 6 equal balls and gently press each ball into 1/2-inch thick disks.
Place the biscuits on a baking sheet and bake for 20 to 25 minutes, or until a wooden pick inserted in the center of a biscuit comes out clean. Allow the biscuits to cool on a rack for 10 minutes. Serve warm.
Makes: 6