Preheat oven to 475ºF (246ºC). Lightly grease a baking dish or cast-iron skillet.

In a large bowl, combine 2 cups (226 g) self-rising flour and 2 pinches (1 g) kosher salt.

Cut 3 tablespoons (35 g) shortening and 1 tablespoon (14 g) very cold butter into the flour mixture with a pastry cutter or two knives until the mixture resembles coarse crumbs with some pea-sized pieces.

Make a well in the center, then slowly pour in 1 cup (245 g) buttermilk while stirring gently with a fork or spatula until the dough just comes together. Do not overmix.

Turn the dough onto a lightly floured surface and gently pat it into a round about 1/2 inch thick. If sticky, dust your hands and the surface lightly with flour.

Use a sharp metal or glass cutter to cut the biscuits straight down (do not twist). Gather the scraps, press gently (no more than one or two light pats), and cut remaining biscuits.

Place the biscuits upright in the prepared baking dish or skillet, leaving a little space between them if you want crisp sides or placing them touching for softer sides.

Brush the tops lightly with 1 tablespoon (14 g) melted butter, if using.

Bake in the preheated oven for 10–12 minutes, until the tops are golden brown.

Remove from the oven and let the biscuits cool briefly in the pan for a few minutes before serving.