In a bowl, mix the flour, baking powder, baking soda, salt, and sugar. Mix in the butter until the mixture resembled coarse crumbs. Mix in buttermilk and then turn out onto a floured surface and kneed for 2 minutes.
Roll into a 6x6 inch square and divide into 12 sections before transferring to an un-greased cooking sheet. Do not separate.
Bake for 15 minutes in the preheated oven until a knife inserted into teh center of the square comes out clean. Separate the biscuits and server warm.