In salted water boil the pasta until al dente state. While the pasta is cooked, put shrimp in the pan, cover, and turn the maximum fire. As soon as the ice has melted, add a handful of coarse salt, two or three sprigs of fresh thyme, and covered with a lid, cook the shrimp for about 10 minutes. Prepared shrimp cool and clean. When the pasta is ready, drain the water, add three to four tablespoons of pesto and mix well. Serve spaghetti with shrimps and fresh basil leaves.