Bring 3 liters of water to a boil in a large pot with 1.5 tbsp salt. While the water heats, mince the garlic cloves finely and have all other ingredients measured and ready: drain and rinse the capers to remove excess salt, zest the lemon, measure out the lemon juice, and have the tuna, anchovies, parsley, chili flakes, and extra virgin olive oil within arm's reach. This prep work ensures you can move quickly once the pasta enters the pot.

Once the water reaches a rolling boil, add the spaghetti and cook for 1 minute less than the package directions—this ensures the pasta finishes cooking perfectly when tossed with the warm sauce. About 1 minute before the pasta is done, reserve 1 cup of the starchy pasta water in a separate container, then drain the pasta thoroughly. I always use Barilla because it holds that perfect al dente texture, and the pasta water starch is crucial for creating a silky sauce.

In the same pot you used for pasta (no need to wash it), heat the oil drained from the canned tuna over medium heat. Once shimmering, add the minced garlic and anchovy fillets, stirring constantly for about 1 minute until the anchovies dissolve into the oil and the garlic becomes fragrant. Sprinkle in the chili flakes and stir for another 15 seconds to bloom the heat. This technique creates a deeply flavored base that will coat every strand of pasta.

Add the drained spaghetti from Step 2 to the aromatic oil mixture and toss to coat evenly. Pour in 1/3 cup of the reserved pasta water and stir continuously for 2 minutes, allowing the starch to emulsify and create a cohesive sauce. Add the rinsed capers during this tossing process. I prefer rinsed capers because they control the saltiness while still providing that briny, acidic note that defines this dish.

Remove the pot from heat. Gently fold in the canned tuna (breaking it into bite-sized chunks as you add it), fresh parsley, lemon zest, lemon juice, 1/2 tsp salt, and black pepper. Drizzle with the extra virgin olive oil and toss gently for about 30 seconds to incorporate everything without breaking down the tuna too much. The fresh lemon juice and zest provide brightness that cuts through the richness of the oil and tuna.

Divide the pasta between bowls or plates and serve right away while the flavors are vibrant and the pasta is still warm. If the pasta seems dry while tossing, add a splash more of the reserved pasta water to loosen it, as the pasta will continue to absorb liquid.