- Bring a large pot of water to the boil. Once boiling, add a generous amount of salt.
- While the water is boiling, remove the ribs and stems from the centre of each kale leaf.
- Quickly blanch the kale in the salted water until vibrant green and slightly wilted, 15 to 30 seconds. Then, using tongs, transfer the kale to a large plate or platter and allow to cool slightly. You can then use the same pot of boiling salted water to cook the pasta.
- Once slightly cooled, drain the kale and wring out the excess water using your hands (use gloves so as not to burn yourself).
- Using a high-powdered blender or food processor, blitz together the pistachios, garlic, olive oil and water until smooth.
- Add the Grana Padano and kale and blend until smooth. If necessary, add 1 tablespoon of water at a time to loosen.
- Transfer the pesto to a large bowl. Taste and season with salt and pepper (and optionally, a squeeze of fresh lemon juice).
- To serve: drain the pasta, reserving a little bit of the pasta water. Add the cooked pasta to the large bowl with the pesto and a splash of pasta water and toss until the sauce nicely coats the pasta. Divide into bowls, serve and enjoy!