1. Clean the cuttlefish, maintaining the ink sac intact. Then cut the flesh into julienne strips.
2. In a high sided pan fry the chopped onion and a whole clove of garlic in the evo oil. When it is well-sautéed remove the garlic and add the cuttlefish, leave to brown and deglaze with white wine.
3. After the cuttlefish has browned, add the tomato pulp and ink to obtain an even black mixture, season to taste and cook for 15/20 minutes over a moderate heat.
4. Clean the prawns, removing the shell and taking care to keep the content of the heads.
5. Finely chop the tails of the prawns for the tartare.
6. Boil the tagliatelle in plenty of salted water for half their cooking time.
7. Add the cuttlefish sauce, the pasta, the secretions from the prawn heads and the yellow tomatoes and cook over a high heat.
8. Finish cooking the pasta in the pan, adding the pasta cooking water from time to time.
9. Serve accompanied by the prawn tartare.