Cook the pasta in a pan of boiling salted water according to the packet instructions. Meanwhile, peel the garlic. Tear the stems out of the cavolo and discard, adding the leaves and the garlic to the pasta pan for 5 minutes. Pour 1½ tablespoons of extra virgin olive oil into a blender, then finely grate in the Parmesan. Use tongs to carefully transfer the cavolo leaves and garlic straight into the blender and blitz for a few minutes until super-smooth. Taste and season to perfection with sea salt and black pepper. Drain the pasta, reserving a mugful of cooking water. Return it to the pan and toss with the vibrant green sauce, loosening with a splash of reserved cooking water, if needed, then divide between your plates. Dot over the ricotta, drizzle with a tiny bit of extra virgin olive oil, and tuck right in.