Spaghetti with Tuna, Onion and Pecorino

Method

1. Heat a pan with olive oil over low heat.
2. Slice the onions (Montoro and/or golden) and add them to the pan with a pinch of salt to help them wilt.
3. Cook the onions slowly, stirring occasionally, for about 10 minutes until they are well wilted.
4. While the onions cook, cut a piece of fresh tuna into large cubes.
5. Heat a separate non-stick pan over high heat with a little oil and sear the tuna cubes until they have a nice crust on the outside, but are still rare inside. Set aside.
6. After the onions have cooked for 10 minutes, add a splash of vinegar or white wine to remove the strong onion taste.
7. Add a couple of bay leaves and sage leaves to the onions.
8. Add half a teaspoon of chilli (or to taste) to the onions.
9. Continue cooking the onions for another 10 minutes, until they are soft and caramelised but not too dark.
10. Meanwhile, bring a pot of salted water to a boil and cook the spaghetti until al dente.
11. Grate the pecorino romano cheese.
12. Remove the bay leaves and sage from the onion pan.
13. Add a splash of pasta cooking water to the onions to create a sauce.
14. Drain the spaghetti one minute early and transfer it to the onion pan.
15. Add most of the seared tuna cubes to the pan, reserving some for garnish.
16. Toss everything together over low heat, adding more pasta water as needed to create a creamy sauce.
17. Remove the pan from the heat and let it cool slightly.
18. Add the grated pecorino romano and toss vigorously to create a creamy emulsion.
19. Add a little more pasta water if needed, then grate some lemon zest over the pasta.
20. Add a generous grind of black pepper and toss again.
21. Plate the pasta, top with the reserved tuna cubes, a few sage leaves for decoration, and an extra grind of black pepper.