Preheat the oven to 450 and butter a large cast-iron skillet – I used my 12-inch pan. In a large bowl, whisk together both flours, the baking powder, sugar, salt and baking soda, then add in the shortening and use your fingers to pinch it completely into the dry mix.

Using a box grater, grate the frozen butter into the bowl using the large holes and toss it all together until the butter is well coated. Pour in the buttermilk and using a stiff spatula (or your hands), gently mix until the dough forms a shaggy mass. Scrape the dough into a large blob and try to divide it into fourths, then eighths, ultimately ending up with 16 even-ish blobs of dough. Perfection is NOT required…these are biscuits…have another look at my photo if you doubt! Drop the dough mounds into your prepared skillet, leaving an inch in between each if you can, and bake for about 20 minutes until they’re a lovely golden brown.