Wash the cavolo nero in cold running water to remove any dirt then blanch in a pot of boiling water for around 2-3 minutes. Drain and rinse in cold water then squeeze as much water out as possible. *See note 1
Make sure to remove any larger, chunky stalks from the cavolo nero then add it to a food processor with freshly grated parmesan, pine nuts, garlic peeled but still whole, nutmeg and a pinch of salt and pepper. Taste for seasoning.
Blitz to a thick paste adding 2 tbsp of water while the motor is running to loosen (water will be added later).
When you're ready to make the pasta, boil it in a pot of salted boiling water until al dente (follow packet instructions).
Reserve 2 cups of pasta water.
Drain the pasta and add it back to the hot pot. Add a couple spoonful of cavolo nero pesto to the pasta and gradually add the reserved pasta water until it coats the pasta evenly. *see note 2.
Serve in bowls and top with flaked almonds.
Notes
(1) 200g (7 oz) cooked weight of cavolo nero
Use a salad spinner to squeeze the water out or place the cavolo nero in a clean tea towel, pinch the four corners together and shake the water out.
(2) You won't need all the water. Add more pesto to your liking and adjust the texture with more pasta water.