Flaky Cheddar Parmesan Cracked Pepper Biscuits

Steps

1. Freeze the butter for at least 30 minutes, then grate it on the large holes of a box grater and return the shreds to the freezer while you measure everything else.
2. Divide the ingredients before you start: set aside 15 g of the Parmesan for the tops and 20 g of the buttermilk for brushing; the remaining Parmesan and buttermilk go into the dough.
3. In a large bowl, whisk the flour, baking powder, baking soda, salt and black pepper.
4. Add the frozen grated butter and toss with your fingertips until every shred is coated with flour. Toss in the cheddar, the dough portion of the Parmesan and the green onion.
5. Pour in the dough portion of the buttermilk and stir with a fork just until a shaggy dough forms with some dry bits remaining.
6. Turn the dough onto a lightly floured counter and pat it into a rectangle about 1 inch thick. Fold it in thirds like a letter, turn it 90 degrees and pat it out again. Repeat for 4 folds total; the dough will turn smooth and layered.
7. Line a baking sheet with parchment. Pat the dough into an 8-by-6-inch rectangle about 1 inch thick, trim a thin strip from each edge to expose the layers, and press the trimmings onto the top. Cut into 12 squares (3 by 4) with a sharp knife, pressing straight down without twisting.
8. Set the biscuits on the baking sheet, almost touching so they rise tall, and chill in the fridge for 15 minutes. Meanwhile, preheat the oven to 425°F (220°C).
9. Brush the tops with the reserved buttermilk and sprinkle with the reserved Parmesan.
10. Bake 16 to 20 minutes, until tall and deep golden on top and bottom, with the cheese on top crisp and browned.
11. Cool on the pan for 10 minutes before pulling the biscuits apart and serving warm.