Clean the black cabbage and spring onion and boil them for 15 minutes in salted boiling water. Drain them, taking care not to throw away the cooking water, and blend them together with two tablespoons of oil using an immersion blender. Set aside. Season with salt and pepper.

Dice the sweet potato and cook it, together with the pasta, in the water previously used for the black cabbage and spring onions. Drain everything and season with the vegetable cream.

Complete with flakes of spicy aged Provolone Valpadana DOP and serve.