Adjust oven rack to middle position and heat oven to 450degrees. With a fork, mix flour, baking powder, baking soda, sugar and salt in a medium bowl. Using the large holes on a box grater, coarsely grate butter into the dry ingredients, mix quickly with fingertips to blend evenly. Stir in buttermilk with fork and mix until dough just comes together. If necessary, add extra droplets of buttermilk over any dry patches.

Turn dough out onto floured work surface and pat into a thick disk about 6 inches across. Cut in half with a knife, then cut each half into five parts. Pick up each piece and gently, without over handling the dough, shape into a round. Spray a 9 inch cake pan with cooking spray and arrange biscuits in pan.

Bake until golden brown, about 20 minutes. Serve immediately