Preheat oven to 425 degrees F. In a large mixing bowl, combine flour, baking powder and salt. Grate in frozen butter and using your hands, pinch and mix until mixture resembles coarse crumbs.
Add cheese and bacon and fold once or twice to combine throughout. Drizzle in 1 cup buttermilk and club soda. Carefully mix with your hands until just combined.
Dump mixture onto a floured surface and pat into a 1-inch thick rectangle with your hands. Fold in 1/3 of the dough then the other third to make a smaller, thicker rectangle. Pat out to a 1-inch thick rectangle again. Using a floured biscuit cutter, cut dough into circles by pressing straight down and pulling up. Place biscuits in a greased cast iron skillet, allowing them to touch. Brush tops with remaining 2 tablespoons buttermilk.
Bake for 15 to 20 minutes, until golden brown.