2½ tsp. Diamond Crystal or 1½ tsp. Morton kosher salt
1 tsp. freshly ground black pepper
1¾ tsp. baking powder
½ tsp. baking soda
1¼ tsp. sugar
2½ cups (313 g) all-purpose flour, plus more for surface
1¼ cups sour cream, plus more for serving
¾ cup hand-grated cheddar
flaky sea salt
Instructions
Place a rack in middle of oven; preheat to 425 deg F. Line a baking sheet with parchment paper. Thinly slice scallions crosswise (not on a diagonal); set aside.
Melt 2 tablespoons of the unsalted butter and set aside.
Whisk salt, black pepper, baking powder, baking soda, sugar, and all-purpose flour in a large bowl to combine.
Cut remaining 10 tablespoons chilled unsalted butter into ½ inch pieces.
Add cut butter to dry ingredients and toss to coat. Work butter into dry ingredients, smashing it between your fingers and flattening to make pea-size bits. Add reserved scallions and ½ cup of the cheese toss to evenly distribute.
Create a well in the center of mixture and add sour cream to the center. Using a fork and working in circles, mix until large shaggy clumps form. Fold dough over itself a couple of times.
Turn out onto a lightly floured surface and knead once or twice until it comes together, using more flour if needed to prevent sticking.
Pat dough into an 8x4-inch rectangle about 1 inch thick.
Starting with a short side, fold dough in thirds as you would a letter. It doesn’t need to overlap perfectly. Pat dough into another 8x4-inch rectangle, then fold dough in thirds like a letter one more time. Pat dough back into an 8x4-inch rectangle and straighten up the edges with your hands and/or your bench scraper. This folding makes the flakiness.
Cut rectangle in half lengthwise, then cut each half crosswise into 5 squares for a total of 10 biscuits.
Transfer biscuits to prepared baking sheet. Brush tops gently with melted butter; sprinkle with flaky sea salt and cheddar.
Bake biscuits until golden brown, 16-20 minutes. Serve warm with butter.
Recipe by story of a kitchen at https://www.storyofakitchen.com/breakfast-recipes/scallion-and-sour-cream-biscuits-with-cheddar/