Grate the cold butter and place it in the freezer, while you get everything else together. The extra cold butter creates steam pockets in the dough when baking and gives these biscuits a lovely, fluffy texture.
Preheat the oven to 425℉ and butter the bottom and sides of a 10-inch cast iron skillet. If you don’t have a cast iron skillet, you can also use a round baking pan.
Mix together the 4 cups of flour, sugar, baking powder, and salt.
Add the chilled butter to the dry ingredients and gently toss to distribute.
Pour the buttermilk and heavy cream into dry ingredients and gently stir until just barely combined.
Place the remaining ½ cup of flour in a bowl. Use a scoop, spoon, or a ½ cup measuring cup to shape the dough (you’ll want them to be a scant ½ cup in size). Place the dough into the bowl with the extra flour. Coat with a light dusting of flour. Gently shake off the excess flour, and place each biscuit tightly into the skillet. You’ll want them to be very close together with all sides touching.
Bake the biscuits for 35 minutes or until golden brown.
Pour the melted butter over the biscuits as soon as they are out of the oven, and sprinkle with flaky sea salt.
Serve and enjoy!