Sift both types of flour into a large bowl and mix in the dried sage, a pinch of salt and some pepper. Without handling the butter, drop it into the flour mix and, using a blunt knife, mix the grated butter into the flour to coat it all evenly. Sprinkle over 2 tablespoons of ice-cold water and mix in with the knife, then gradually add a further 2–3 tablespoons of water until the mix starts to come together.