Cook the spaghetti al dente according to the instructions on the packet. Remove the stalk from the savoy cabbage, cut into strips and add to the pasta water 3-5 minutes before the end of the cooking time.
For the sauce, roughly chop the walnuts and finely puree 30 g of them together with the clove of garlic, olive oil, walnut oil, lemon juice and 4-5 tablespoons of the pasta boiling water until a creamy sauce is obtained. Season to taste with salt and pepper.
Drain the pasta and savoy cabbage and place in a bowl. Add the sauce and parmesan (important: use freshly grated parmesan, not this dry powder) to the hot noodles and savoy cabbage and mix. Serve sprinkled with the remaining walnuts and some parmesan.