- 4 1/2 teaspoons active dry yeast (from two 1/4-ounce envelopes)
- 1/4 cup warm water (100 degrees to 110 degrees)
- 5 cups all-purpose flour, plus more for dusting
- 1 tablespoon baking powder
- 1 teaspoon baking soda
- 2 1/2 tablespoons sugar
- 1 teaspoon coarse salt
- 2 sticks cold unsalted butter, cut into small pieces, plus 1/2 stick butter, melted and cooled, for brushing
- 2 cups buttermilk
Preheat oven to 450 degrees. Line a baking sheet with parchment; set aside. Dissolve yeast in warm water and let stand until foamy, 5 to 10 minutes.
Whisk together flour, baking powder, baking soda, sugar, and salt in a large bowl. Transfer half of mixture to a food processor and add butter. Pulse until mixture resembles coarse meal with some blueberry-size clumps. Return to remaining flour mixture in bowl and mix to combine. Make a well in center of bowl and add yeast mixture and buttermilk. Stir until a dough forms, then turn out onto a floured work surface. Knead until dough is smooth and no longer sticky, about 5 minutes.
Roll out dough to 1/2-inch thick and cut out 1 1/2-inch rounds with a biscuit cutter. Set rounds 1 inch apart on baking sheet, brush tops with melted butter, and bake until lightly golden (do not let brown), 10 to 12 minutes. Serve warm or at room temperature.