Finely chop 3 garlic cloves and 1/2 red onion. Dice the green olives, chop the parsley, and cut the 1/2 lemon into wedges.

Bring a large pot of salted water to a boil. Cook 340 g linguine until al dente according to the package timing.

Heat 1 tablespoon olive oil in a frying pan over medium-high heat. Sear the 170 g fresh tuna steak for about 1 to 2 minutes per side.

Transfer the seared tuna steak to a plate. Reserve it while preparing the sauce.

Add the remaining 1 tablespoon olive oil and the chopped garlic to the same frying pan. Fry for about 1 minute until fragrant without browning.

Stir 1 tablespoon tomato paste into the garlic oil. Fry it for 1 minute to deepen its flavor and reduce acidity.

Add the chopped red onion, 2 teaspoons capers, and half of the diced green olives. Sauté for 2 to 3 minutes until the onion softens.

Add 280 g canned tuna and break it into chunks. Flake about half of the seared tuna steak into the pan.

Pour 400 g crushed tomatoes into the pan. Simmer the sauce for 5 minutes over medium heat.

Stir 200 ml heavy cream into the tomato sauce. Add 120 ml pasta cooking water and stir until the sauce is glossy and loose.

Lift the cooked linguine directly from the pot into the sauce using tongs. Toss for 1 to 2 minutes until the pasta is thoroughly coated.

Season the pasta with black pepper and adjust salt if needed. Stir in the chopped parsley.

Divide the pasta among 4 plates and scatter over the remaining diced green olives. Top each serving with a piece of reserved seared tuna.

Squeeze lemon over each serving and drizzle with olive oil. Serve immediately while hot and creamy.