Preheat oven to 450°F.

Place the 1 1/2 cups cake flour, baking powder, salt, and sugar in a medium mixing bowl and mix well with a fork.

Add the cold butter pats and work into flour with a pastry blender until a coarse meal is achieved.

Add the 1/2 cup buttermilk and egg yolk and mix with a fork. The dough should come together. If it seems dry, add a little more buttermilk until the dough comes together.

Turn out/Transfer the dough to a board that has been dusted with the 3 Tbsp cake flour. Knead 12-15 turns, incorporating a bit of the flour with each turn. Discard any excess flour.

Shape dough in to a ball an flatten with your fingers/palm to a 7 1/2 inch circle. Cut like a pizza in 8ths. Transfer biscuits to a baking tray and leave room for spreading out.

Brush the tops of biscuits with some softened unsalted butter, using a pastry brush.

Bake biscuits on the center rack of oven for 12-14 minutes.

Serve hot from the oven. These biscuits reheat better than any others I have made (in a 350°F oven until well warmed).