½ cup warm water (100 to 110 degrees)
1 (¼ ounce) package active dry yeast (2¼ teaspoons)
1 teaspoon plus 3 tablespoons granulated sugar, divided
5 cups all-purpose flour
1 tablespoon baking powder
1½ teaspoons salt
1 teaspoon baking soda
½ cup cold salted butter, cubed
½ cup cold shortening, cubed
2 cups whole buttermilk
6 tablespoons salted butter, melted and divided
Stir together warm water, yeast, and 1 teaspoon of the sugar in a small bowl. Let stand 5 minutes.
Stir together flour, baking powder, salt, baking soda, and remaining 3 tablespoons sugar in a large bowl; cut cold butter and cold shortening into flour mixture with a pastry blender or 2 forks until crumbly. Add yeast mixture and buttermilk to flour mixture, stirring just until dry ingredients are moistened. Cover bowl with plastic wrap; chill at least 2 hours or up to 5 days.
Preheat oven to 400 degrees. Turn dough out onto a lightly floured surface, and knead 3 or 4 times. Gently roll into a ½-inch-thick circle, and fold in half; repeat. Gently roll to ½-inch thickness; cut with a 2-inch round cutter. Reroll remaining scraps, and cut with cutter. Place rounds with sides touching in a 12-inch cast-iron skillet or on a parchment paper-lined baking sheet. (If using a 12-inch skillet, place remaining biscuits in a 10-inch skillet or on a baking sheet.) Brush biscuits with 3 tablespoons of the melted butter.
Bake in preheated oven until golden, 15 to 20 minutes. Brush with remaining 3 tablespoons melted butter, and serve.
Makes 10 to 12
You don't have to use all the biscuit dough at once. Refrigerate what you don't use in an airtight container for up to five days.