Preheat your oven to 425°F (220°C) and line a baking sheet or grease it lightly.
In a large bowl whisk together the All-Purpose Flour, Baking Powder, Baking Soda, and Kosher Salt until evenly distributed.
Cut cold, cubed Unsalted Butter into the dry ingredients using a pastry cutter, two knives, or your fingertips until the mixture resembles coarse crumbs with some pea-sized pieces remaining.
Make a well in the center and pour in cold Buttermilk; gently stir with a fork until the dough just comes together—it should be shaggy and slightly sticky. Avoid overmixing to keep the biscuits tender.
Turn the dough onto a lightly floured surface, fold it over a few times to create layers, then pat or roll it to about 1 inch thick. Use a floured biscuit cutter to cut rounds, pressing straight down without twisting.
Transfer the biscuits to the prepared baking sheet—place them close together for taller sides or spaced apart for crisper edges—and bake until puffed and golden on top, about 12–15 minutes.
As soon as they come out of the oven, brush the tops with melted Butter and, if you like, sprinkle a tiny pinch of Kosher Salt over them.
Let the biscuits cool for a few minutes, then serve warm for best texture and flavor.
