卡尔a Hall's Buttermilk Biscuits

Whisk together flour, baking powder, sugar, salt, and baking soda in a large bowl. Add shortening; using your fingertips, pinch and work shortening into flour mixture until mixture resembles coarse cornmeal. Grate butter using large holes of a box grater into flour mixture. Toss and pinch quickly with your fingers until all butter pieces are well-coated in flour mixture, about 30 seconds.

Lightly spray work surface with cooking spray, and sprinkle with flour. (Spray keeps flour in place.) Add buttermilk to flour mixture in bowl, and stir together to form a shaggy, sticky dough with no dry flour remaining. Turn dough out onto prepared work surface. Lightly coat hands with flour; gently pat dough using heels of hands to form a 1/2-inch-thick rectangle (about 11 x 7 1/2 inches). Fold rectangle into thirds (like folding a letter). Repeat process of patting and folding 2 times.

预热烤箱至450°F。使用轻微的2 1/4英寸圆形切割机，切成面团，堆叠，重塑和切碎碎屑，直到使用所有面团。将面团转向光滑的一面；在衬有羊皮纸的烤盘上排列3/4英寸。冷藏，发现，直到冷约15分钟。

Bake chilled dough in preheated oven until tops are golden brown and lightly crisped, 16 to 20 minutes. Let biscuits cool on pan 5 minutes.