Set oven to 450 F
Dice up butter and add in shortening. Chill in freezer while you measure the dry ingredients to keep the butter cold
Add the flour, baking powder, salt, and baking soda to a large mixing bowl and stir to combine
Add butter shortening mix to the dry ingredients and cut the fat into the flour with your fingers. Just reach in, pick up some of the diced butter pieces, and smash them in your fingertips into the flour. Keep doing this until as much of the flour is incorporated into the butter as you can. Try not to let the butter melt
Add buttermilk and stir with spatula to combine all of the flour mixture. It won't be smooth, you just need to get as much of the flour into the dough ball as you can
Tip the dough out onto a floured counter
With a board scraper, press it together into a rough rectangle. Using the scraper, reach under half and fold it onto itself like a playdough book. Keep pressing it down and folding it about 8 times until the dough has a consistent texture.
Use a 2" biscuit cutter or any other round thing really to cut out the biscuits
Place on a baking sheet in the 450 F oven for 10 minutes, rotate pan and bake for another 10 minutes or until they are golden brown on the tops.