Preheat the oven to 425°F and grease a 10-inch cast iron skillet with butter. (You can use a 12 inch skillet if you have more, smaller biscuits.)
Combine dry ingredients in a mixing bowl and give it a quick stir to combine.
Chop cold butter into small pieces and add it into the flour mixture. Mix on low speed until the mixture resembles coarse crumbs.
Pour cold buttermilk into the center of the mixture and mix, still on low, until just combined and dough is sticky.
Take the dough out onto a lightly floured surface and sprinkle with a little more flour on top. Knead dough 5-6 times, folding it on top of itself, and pat into a ½ inch-think circle. (Try to handle it as little or as quick as you can.)
Use a cookie cutter (about 2 to 2 1/2 inches in diameter) to cut out the biscuits.
Rework dough scraps into a ball (kneading it as little as possible) and shape it into a circle again. Cut out more biscuits.
Place biscuits on a prepared cast iron skillet. Brush each biscuits with melted butter. Bake for 12-14 minutes.
As soon as biscuits are out of the oven, brush them with melted butter.
Video
Notes
Storing: You can store baked biscuits at room temperature for up to 2 days. Make sure your container or storage bag is airtight to prevent them from going stale. To keep them fresh a few days longer, store them in the refrigerator for up to a week. Again, be sure to store them in an airtight container or storage bag. You can easily reheat cold biscuits in a microwave for a few seconds.
To freeze baked biscuits: After baking, allow them to cool completely and place them into a freezer zip-top bag. Get as much air out as you can without squeezing biscuits and seal. Freeze for up to 3 months.