In a large bowl, combine flour, salt and baking powder, then grate in the frozen butter. Slowly add buttermilk and stir until you have a soft dough. Turn out dough onto a lightly floured surface and knead just a bit to bring together ingredients.
Press dough into a 4” x6” shape, wrap in plastic film and chill for one hour.
Unwrap dough and roll into an elongated rectangle. Fold in thirds (“letter fold”) first third from the top, second third from the bottom. Turn this 90 degrees (1/4 turn) and roll into another long rectangle. Repeat the letter fold process again.
Flip dough over and roll into a rectangle that is ½” thick. Square off the four sides, cover and put in freezer for 20 minutes.
Set oven to 400 F. Remove dough from freezer and cut 9 pieces with a sharp knife.
Place a sheet of parchment on your baking sheet. Lay pieces on pan, keeping a little space between them. Brush tops with a little more buttermilk then bake for 20-30 minutes or golden brown. Let cool slightly then enjoy with butter, jam or honey.