Boil a large pot of salted water. Add spaghetti and cook al dente, about 10 minutes, or follow instructions on pack.
A few minutes before pasta is cooked add shredded kale to the water and stir gently.
Scoop out about ¼ cup of pasta water and set aside. Drain the pasta and kale in a colander and return it to the pot. Add the pesto and toasted walnuts and some of the reserved pasta water (if needed). Gently toss to combine and add extra seasoning to taste. Serve at once, with extra pesto on the side if desired. Or alternatively drizzle with a little extra Udo’s Choice oil.