Place the yoghurt, blue cheese, hot sauce, garlic granules and water in a bowl and blitz with the stick blender until a smooth, creamy coating consistency is achieved. Add a little more water if needed.
Add the cabbage, carrots and spring onions (reserve a few green slices for garnish) and toss in the dressing until well coated.
Season with salt and pepper.
Pile into a serving bowl, sprinkle on the reserved spring onion and drizzle over a little more hot sauce if you like, and serve.