Adjust rack to upper half of oven and preheat to 450˚F.
Sift flour, sugar, salt, baking powder and baking soda into a large mixing bowl.
Cut butter into dry ingredients with a pastry blender or two butter knives, until mixture looks like a coarse meal. Add buttermilk and stir into a shaggy dough.
Turn dough out onto a lightly floured work surface and knead gently about 10 times. Roll or pat dough to ½-inch thick loose round or rectangle. Dip 2 ½-inch diameter biscuit cutter into flour and cut biscuits straight down (for maximum height and layers resist the urge to twist the cutter). Transfer to ungreased baking sheet and bake in 10 to 12 minutes or until golden brown. Serve hot or warm.
Once you've cut the biscuit dough, you can freeze for later baking. Freeze on a baking sheet, transferring to a freezer bag once frozen. Bake at 450˚F from frozen (my preference) or thaw in the refrigerator overnight. If baking from frozen, add a minute or two to baking time.