Activate yeast:

Stir together warm water, yeast, and 1 teaspoon of the sugar in a small bowl. Let stand 5 minutes.

Blend butter, shortening, and dry ingredients:

Stir together flour, baking powder, salt, baking soda, and remaining 3 tablespoons sugar in a large bowl; cut cold

butter and shortening into flour mixture with a pastry blender or 2 forks until crumbly.

Add yeast mixture and buttermilk:

Add yeast mixture and buttermilk to flour mixture, stirring just until dry ingredients are moistened.

Chill dough:

Cover bowl with plastic wrap; chill at least 2 hours or up to 5 days.

Knead dough:

Preheat oven to 400°F. Turn dough out onto a lightly floured surface, and knead 3 or 4 times. Gently roll into a 1/2-

inch-thick circle. Fold in half; repeat.

Cut out biscuits:

Gently roll to 1/2-inch thickness; cut with a 2-inch round cutter. Reroll remaining scraps, and cut with cutter. Place

rounds with sides touching in a 10- or 12-inch cast-iron skillet or on a parchment paper-lined baking sheet. (If

using a 10-inch skillet, place remaining biscuits on a baking sheet.)

Brush biscuits with 2 Tbsp. of the melted butter.

Bake biscuits:

Bake in preheated oven until golden, 15 to 20 minutes. Brush with remaining melted butter, and serve.