Cut purslane from the root, wash and drain well. Take a handful of leaves aside. Roast pine nuts in a pan without fat. Peel and chop the garlic.
Prepare the pasta in boiling salted water according to the instructions on the packet. In the meantime purslane, 2 tablespoons of water, garlic and oil, then add grated cheese and pine nuts. Puree again and season to taste with salt and pepper.
Drain the pasta and put it back into the pot. Add the pesto and mix well. Finally add the remaining purslane leaves. Arrange the pasta and garnish with parmesan shavings.