Sour Cream Dill Black Pepper Biscuits

Steps

1. Before you start, freeze 140 g of the butter (about nine-tenths) for 20 minutes, then grate it on the large holes of a box grater and return it to the freezer. Keep the remaining 15 g of butter aside for brushing.
2. Whisk the cold sour cream with 115 g of the milk (most of it) until smooth and keep it in the fridge; save the remaining 15 g of milk for later.
3. In a large bowl, whisk the flour, baking powder, baking soda, sugar, salt and black pepper. Stir in the dill so it coats evenly.
4. Toss the frozen grated butter into the flour mixture with a fork until every shred is coated.
5. Pour the sour cream mixture over the flour and stir with a spatula just until a shaggy dough forms; if dry bits remain at the bottom, drizzle in the reserved 15 g of milk.
6. Turn the dough onto a lightly floured counter and pat it into a rectangle about 3/4 inch thick. Fold it in thirds like a letter, turn it a quarter turn and pat out again. Repeat the fold and pat two more times for flaky layers.
7. Pat the dough into a 6-by-8-inch rectangle about 1 inch thick, set it on a parchment-lined baking sheet and chill for 20 minutes. Meanwhile, heat the oven to 425°F (220°C).
8. With a sharp knife or bench scraper, cut the chilled dough straight down into 12 squares (no twisting) and space them on the sheet about 1 inch apart.
9. Melt the reserved 15 g of butter and brush it over the tops.
10. Bake 15 to 18 minutes, until tall, golden on top and golden at the edges, and a toothpick in the center of one comes out clean.
11. Cool on a rack for 5 minutes before serving warm.