Line a baking sheet with foil or parchment
Combine all purpose flour, salt, sugar, baking powder and baking soda together in a large bowl
Stir to incorporate, set aside
Grate the frozen butter with the cheese grater
Add to shortening and toss together
Rub the butter mix into the flour until the mixture resembles coarse crumbs
Add the buttermilk to the flour mixture and gently mix until there’s no dry bit of flour left over, the dough will be sticky.
Lightly coat you’re working space with flour your work surface
Turn the dough out onto the prepared surface and gently pat into a half inch thick rectangle
Sprinkle the dough with flour, then fold it in thirds as if mailing a letter
Repeat that two more times
Pat the dough into a 3/4 inch thickness it should no longer be sticky at this point
Dip your biscuit cutter into flour and then cut out as many biscuits as you can, dip in flour as needed
Stack the scraps and pat them into a 3/4 inch thickness and cut once more
Place biscuits on prepared sheet
Chill the biscuits for 15 minutes
Meanwhile preheat the oven to 450°
Bake until the tops are golden and crisp, about 15- 16 minutes
Let cool for five minutes on the pan before serving.