Instructions

• Place an oven rack in the upper third (top rack) and preheat oven to 450°F (230°C).
• In a large bowl, whisk together 2 cups bread flour, 1 tablespoon baking powder, 1/4 teaspoon baking soda, and 1/2 teaspoon salt.
• Add 2 tablespoons sour cream to the dry ingredients and stir briefly to distribute.
• Using the large holes of a cheese grater, grate 3/4 cup frozen unsalted butter directly into the flour mixture. If the butter warms while grating, return it to the freezer for a few minutes.
• Add the grated butter to the flour mixture and quickly stir, then cut the butter into the flour with a fork until the mixture resembles coarse crumbs with some pea-sized pieces. Work quickly to keep the butter cold.
• Pour in 2/3 cup buttermilk and stir gently until the dough just comes together. If the dough seems too dry, add more buttermilk up to a total of 3/4 cup, a little at a time, until it holds together. Do not overmix.
• Turn the dough out onto a lightly floured surface. Fold it a couple of times and use a rolling pin or your hands to roll/press it to 1-inch thickness.
• Using a 3-inch biscuit cutter, cut 6 biscuits by pressing straight down without twisting. Gather scraps, gently re-pat to 1-inch thickness, and cut remaining biscuits as needed to total 6.
• Place the biscuits on a baking sheet (touching edges if you prefer taller sides, or spaced slightly apart) and transfer to the preheated oven on the top rack.
• Bake for 12 minutes. While the biscuits bake, melt 1 tablespoon butter.
• Remove the biscuits from the oven after 12 minutes, brush the tops with the melted butter, then return them to the oven and bake an additional 1 to 2 minutes, or until the tops are golden brown.
• Remove biscuits from the oven and let cool briefly on the baking sheet before serving.