Preheat oven to 450°F (230°C). Line a baking sheet with parchment paper. Keep aside.

Add the cold cubed butter into the flour  mixture. Using a pastry cutter cut it until it resembles coarse meal and no large pieces of butter remain.

Pour the cold buttermilk into  the bowl and mix until the dough comes together.The dough will be slightly sticky and crumbly.

Transfer the dough on a lightly floured working surface and form 1-inch ( 2 cm) thick rectangle.  Fold it in thirds.  Again pat it into a rectangle and fold in thirds. Repeat 2-3 times.

Finally, roll the dough or pat down  into 1/2 -inch ( 1 cm) thick rectangle. Using a 2.5-inch (6.5 cm) cookie cutter, cut out the rounds and place them on the prepared baking sheet. Gather all the scrap pieces of the dough, form a rough rectangle and cut out more rounds. Brush the tops of the biscuits with buttermilk.

Bake for 17-20 minutes in the preheated oven until lightly golden brown.

Remove from the oven and allow to cool down for 5 minutes before serving. You can brush the tops with melted butter if desired.