Preparation

• Heat the olive oil in a sauté pan over medium heat. Add the onion and cook until very soft and lightly caramelized, about 15 minutes. Meanwhile, bring a large pot of water to a boil, salt it generously, and cook the pasta. When the pasta is al dente, drain it and keep it warm (reserve about 1/2 cup of the cooking water to loosen the finished dish, if necessary).
• Add the garlic to the onion and cook, stirring frequently, until the garlic is soft and fragrant, about 1 minute. Add the chopped tomato, sun-dried tomatoes, lemon zest, and lemon juice and simmer briefly. Add the tuna, olives, and parsley and season with salt and pepper to taste. Heat through and toss with the hot pasta, adding a few drops of the pasta water to moisten the dish, if you like. Serve immediately.