Laminated buttermilk biscuits

Grate the frozen butter on the largest holes of a box grater into clean, separate flakes; keep it cold.

Stir together 425 g all-purpose flour, 8 g salt, 15 g sugar, 15 g baking powder and 3 g baking soda in a medium bowl, then add the frozen butter.

Quickly crumble the butter flakes into the flour to a gravelly texture, before body heat warms the butter.

Drizzle in 300 g buttermilk while stirring to prevent lumps.

Flip onto a liberally floured board and press into a rough rectangle.

Roll to about 18 inches long and give a book fold: top third over the middle, bottom third over both; turn 90 degrees.

Roll and fold again; after fold two, turn 90 degrees and flip so the shaggier side faces up; repeat for five folds in all, re-flouring before the fifth.

Flip folds-down and pound with the rolling pin to seal and flatten; refrigerate about 10 minutes to firm the butter and relax the gluten.

On a floured surface, roll slowly and firmly, turning 90 degrees, into an evenly thick roughly 10-inch square, working quickly.

Trim the edges with a floured bench scraper and cut nine roughly even squares, cutting cleanly so the butter does not smear.

Move to a parchment-lined sheet tray, preheat the oven to 400F and freeze the biscuits about 20 minutes.

Brush the tops liberally with melted butter and bake at 400F for 20 to 24 minutes, turning the tray halfway; these took about 21 to 22 minutes.