Dissolve soda in buttermilk; stir well, and set aside.
Combine flour, brown sugar, cinnamon, and salt; stir well. Cut in shortening with a pastry blender until mixture resembles coarse meal. Reserve 1/4 cup plus 2 tablespoons flour mixture for topping.
Make a well in center of remaining flour mixture. Add buttermilk mixture; stir until dry ingredients are moistened.
Spoon batter into a greased 8- inch square baking pan; sprinkle reserved flour mixture over batter. Bake at 400° for 35 minutes or until a wooden pick inserted in center comes out clean. Cool in pan 10 minutes. Sprinkle with powdered sugar, and cut into squares.
Oxmoor House Homestyle Recipes