Preheat oven to 425F. Spray a large cast iron skillet with nonstick cooking spray, or line a baking sheet with parchment paper or Silpat.

Place buttermilk in the freezer, and chill until it is very cold, about 10 minutes.

In a large bowl, whisk together flour, baking powder, baking soda, sugar, salt, cayenne pepper, and parsley.

Once the buttermilk is chilled, stir the melted butter into the buttermilk. The butter should form into small globs in the milk.

Stir the buttermilk mixture into the flour until just combined. Fold in cheese.

On a clean, floured work surface, roll out the dough and pat down until it's about 1 1/2 - 2 inches thick. Using a 2 1/2 or 3 inch biscuit cutter, cut out the biscuits. Place the biscuits in the prepared cast iron.

Bake for 18-20 minutes, or until biscuits are lightly browned.

If desired, brush hot biscuits with 1 tablespoon melted butter mixed with about 1/8 teaspoon cayenne pepper and 1/8 teaspoon salt.