Preheat oven to 450 degrees and grease a 2 inch deep 9x13-inch baking pan.
In a medium bowl whisk flour, baking powder, and salt. Add shortening and mix well. (You can use a hand mixer for this or you can transfer to a food processor to blend in the shortening.)
Add baking soda to buttermilk. Pour into flour mixture and blend well.
Transfer dough to a well-floured surface. Sprinkle dough with flour and knead a few times but do not over work the dough.
Roll dough out 1/2 inch thick. Use a 2-inch round cookie cutter to cut dough into as many circles as possible. (You could also use a jar lid or drinking glass to cut circles).
Dip the biscuits in the vegetable oil being sure to coat all sides, and place side by side in baking pan. (They should be touching each other).
Bake for 8-12 minutes or until golden brown. Serve hot with butter and jam.
Notes
Some stores carry Knott's Berry Farm boysenberry preserves - this is the ultimate way to finish off these buttermilk biscuits!