4 teaspoons baking powder
1 teaspoon baking soda
1 teaspoon salt
12 tablespoons cold unsalted butter, cut into small pieces
1 1/2 cups cold buttermilk
1/2 cup heavy cream
2 tablespoons coarsely ground black pepper
4 tablespoons unsalted butter, melted
Preheat oven to 450 F.
Combine flour, baking powder, baking soda and salt in the bowl of a food processor. Pulse twice to distribute the ingredients evenly. Scatter the butter over the top of the flour mixture and pulse 4 or 5 times or until the mixture resembles coarse meal. Add the buttermilk and pulse until the mixture just begins to come together.
Scrape the dough onto a lightly floured counter. Pat the dough into a 10 by 12-inch rectangle about 3/4-inch thick. Use a 3-inch round cutter to make 8 biscuits then place them on a baking sheet lined with parchment paper. Press together the scraps of dough, and repeat process. Place the biscuits on another parchment-lined baking sheet; brush the tops with cream and sprinkle with black pepper. Bake the biscuits for 12-15 minutes or until lightly golden brown. Remove from the oven and brush the tops with melted butter.