Add the first seven ingredients to blender and pulse 3-4 times to sift dry ingredients. Add butter and pulse 8-10 times until butter resembles a coarse meal. Add ½ cup buttermilk and pulse 6-8 times. Add other ½ cup buttermilk and cheese and pulse 6-8 times until dry ingredients are just incorporated. Use spatula to scrape sides of blender, then dump biscuit dough onto floured surface.