Step 1: Cook the Pasta

Bring a large pot of salted water to a boil and cook the pasta according to the package instructions until al dente. Reserve ½ cup of pasta water, then drain the pasta and set it aside.

Step 2: Sauté the Aromatics

In a large skillet or pan, heat 2 tablespoons of olive oil over medium heat. Add the chopped onion and cook for 2–3 minutes until softened. Stir in the minced garlic and red pepper flakes, cooking for another 30 seconds until fragrant.

Step 3: Build the Tomato Sauce

Add the diced tomatoes and tomato paste to the pan, stirring well to combine. Season with salt and black pepper, then let the sauce simmer for 10 minutes, allowing the flavors to meld. If the sauce thickens too much, add a splash of the reserved pasta water.

Step 4: Add the Tuna

Gently fold in the drained canned tuna, breaking it up into smaller chunks. Let it simmer in the sauce for 3–5 minutes, allowing it to absorb the flavors. If using capers, add them now for an extra punch of briny goodness.

Step 5: Toss the Pasta

Add the drained pasta to the skillet, tossing everything together until the noodles are evenly coated in the sauce. If needed, add a splash of pasta water to loosen the sauce.

Step 6: Finish and Serve

Remove from heat and stir in a squeeze of fresh lemon juice for brightness. Garnish with fresh basil or parsley and a sprinkle of Parmesan cheese if desired. Serve hot and enjoy!