Step 1: Preheat oven to 425 degrees.
Step 2: In a large mixing bowl, sift flour, sugar, baking powder, baking soda and salt.
Step 3: Using a pastry blender, blend butter into dry ingredients until mixture looks like crumbs.
Step 4: Make a well in the center and pour in the chilled buttermilk. Stir just until the dough comes together. The dough will be very sticky.
Step 5: Turn dough onto floured surface, dust top with flour and gently fold dough over on itself 5 or 6 times. Press into a 1-inch thick round. Cut out biscuits with a 2-inch cutter, being sure to push straight down through the dough. Place biscuits on baking sheet. Reform scrap dough, working it as little as possible and continue cutting.
Step 6: Bake until biscuits are tall and light gold on top, 15 to 20 minutes.