Preheat the oven to 450 degrees F.

Add 3 tablespoons of butter to a large cast iron skillet and place it in the oven until melted.

In a large bowl, whisk together the flour and baking powder.

Use a pastry blender or fork to cut in the butter until the pieces are pea-size or smaller.

Create a well in the middle of the flour mixture and add the buttermilk.

Stir until the ingredients are just combined. The batter will be a little crumbly.

Turn the dough out onto a well-floured surface. With floured hands, bring the dough together and gently fold it over 3 or 4 times.

Pat the dough out to about 1 inch thickness.

Use a floured biscuit cutter (or glass cup) to cut the biscuits.

Place the biscuits into the prepared cast iron skillet, spacing them close together.

Reshape the remaining dough and continue to cut additional biscuits.

Brush the tops of the biscuits with 1 tablespoon of buttermilk.

Bake for 13 to 16 minutes, or until the biscuits are lightly golden brown on top.

Brush the tops with the remaining two tbsp of melted butter and serve warm.