5tablespoonsunsalted buttercold, plus extra for greasing the pan
In a bowl, add flour, baking powder, baking soda, and salt. Whisk to combine and remove clumps. (Or, add to a food processor and pulse a few times).
Grate cold butter using the large side of a box grater and add to flour mixture, tossing to combine. Or, use a pastry cutter to cut cubed butter into flour mixture. (Or, add to food processor and pulse until butter is pea sized. If using a food processor, pour mixture into a large bowl at this time).
Make a well in the center of your flour mixture and add buttermilk. Gently stir until ingredients are mostly incorporated. Dough will look shaggy and sticky. Pour dough out onto a lightly floured surface.
Gently pat dough with lightly floured hands into a large, flat rectangle, about 10-12 inches wide and about ¾ inch thick. Keep extra flour nearby and continually flour the surface, dough, and your hands as needed. Fold dough rectangle in half, turn to the right to make your new rectangle horizontal, and gently pat back into a large rectangle. Repeat 4 times, folding your dough 5 times in total. Pat dough into a large rectangle, about ¾ inch thick.
Using a 2.5 to 3 inch biscuit cutter, cut biscuits out of dough (do not twist your cutter, this will seal the edges). Reform leftover dough gently and continue cutting until all dough is used - you should get about 10 biscuits.
In a skillet (I used a 10 inch cast iron skillet), melt a tablespoon of butter over medium-low to low heat. Add biscuits to pan (you'll likely need to cook in two batches) about 1 inch apart, and cook for 6 minutes on each side. If biscuits appear to be browning too quickly, turn the heat down. Low heat ensures your biscuits cook through in the center without burning on the outside. Add another tablespoon of butter before adding each additional batch of biscuits to the pan.
Do not be tempted to turn the heat up - this will not cook your biscuits faster. Low heat ensures the outside of your biscuits don't burn before the center cooks through.
Homemade biscuits keep for 1-2 days at room temperature in a sealed container, up to 1 week in the refrigerator, or 2-3 months in the freezer. If freezing, seal tightly with foil or plastic wrap and store in a freezer safe container.
Oven baking: Preheat oven to 425 degrees Fahrenheit. Line a baking sheet with parchment paper, or grease a cast iron pan. Place biscuits close together (or touching if possible) for a better rise in the oven. Bake for 16-20 minutes, or until tops are golden brown.