Preheat your oven to 425°F (220°C) to ensure your biscuits rise beautifully.
In a large mixing bowl, whisk together 2 cups bread flour, 1 tablespoon baking powder, 1/4 teaspoon baking soda, and 1/2 teaspoon salt until well blended.
Grate the frozen 3/4 cup unsalted butter directly into the flour mixture. Gently fold the grated butter until evenly distributed.
Add 2 tablespoons of sour cream to the mixture and stir gently to combine.
Gradually pour in 2/3 to 3/4 cup buttermilk, mixing until the dough comes together and is moist but not sticky.
Turn the dough out onto a lightly floured surface. Pat down to about 1-inch thickness and either cut with a biscuit cutter or divide into large pieces by hand for ginormous biscuits.
Place biscuits on a parchment paper-lined baking sheet. Brush tops with 1 tablespoon melted butter for a golden finish.
Bake for about 15-20 minutes until golden brown. Remove from oven and let cool slightly before serving.
Equipment
Mixing Bowl
Grater
Baking Sheet
Parchment Paper
Rolling Pin
Notes
Use frozen butter and grate it for flaky biscuit layers.
Do not overwork the dough to keep biscuits tender.
Make-ahead tip: freeze unbaked biscuits on a baking sheet, then store in a freezer bag for up to 2 months.