Start by boiling water in a large pot. Add the spaghetti and cook until it reaches a firm texture, aim for al dente, meaning it should be tender but still slightly firm. Be careful to avoid overcooking, as mushy pasta will lose the best texture.
In a large pan, add some oil and toss in the anchovies. Let them sizzle until they break down, creating a rich, savory aroma that infuses the oil with flavor, serving as a great base for your sauce.
Introduce the sliced garlic and red chilli flakes to the anchovies in the pan. The garlic should turn golden while cooking, releasing a fragrant aroma. Make sure to stir occasionally to prevent the garlic from browning too much, which can lead to bitterness.
Pour in the tomato passata or crushed tomatoes into the pan, allowing it to bubble gently. The sauce will thicken as it heats up and blends with the anchovy mixture, intensifying the flavor. Keep stirring to avoid sticking.
Gently fold in the canned tuna and drained capers into the sauce. The tuna should flake apart easily while combining with the sauce, adding texture. Avoid overmixing to maintain a balanced consistency.
Taste the sauce and add salt according to your preference. Combine the cooked spaghetti with the sauce in the pan, tossing gently to coat every strand. Take your time with this step to ensure a harmonious mix of flavors and to avoid any dry bites.
Serve the pasta warm, scooped onto plates, and garnish with fresh parsley if desired. The vibrant green will add a bright touch to the dish.
Notes
Store leftovers in an airtight container in the fridge for 2-3 days.