Bring a large pot of salted water to a boil and cook the spaghetti until al dente according to package instructions. Reserve about 1 cup of pasta water before draining the pasta. The starchy water helps create a silky sauce later.
Avoid overcooking the pasta because it will continue cooking slightly in the sauce. Al dente pasta holds the puttanesca sauce much better and gives the dish authentic Italian texture.
Heat olive oil in a large skillet over medium-low heat. Add minced garlic and red pepper flakes, stirring gently for about one minute until fragrant but not browned.
Add the chopped anchovies and stir continuously until they melt into the oil. This step creates the deep savory flavor that makes puttanesca sauce so special and rich.
Pour the crushed tomatoes into the skillet and stir well to combine with the anchovy mixture. Add oregano and black pepper, then let the sauce simmer gently for about 10 minutes.
The tomatoes should thicken slightly while losing their raw taste. Slow simmering also helps balance the salty ingredients and creates a smoother sauce.
Add sliced Kalamata olives and drained capers to the sauce. Stir everything together and let it cook for another 3 to 4 minutes so the flavors blend properly.
The olives and capers give the dish its signature briny taste. They also add texture and make every bite more exciting and flavorful.
Add the drained pasta directly into the skillet with the sauce. Toss everything together until the noodles are evenly coated and glossy.
If the sauce feels too thick, add a little reserved pasta water. This helps the sauce cling perfectly to the pasta without becoming heavy.
Turn off the heat and sprinkle fresh parsley over the pasta. Serve immediately with freshly grated Parmesan cheese if desired.
The warm pasta absorbs all the bold Mediterranean flavors beautifully. A final drizzle of olive oil before serving also adds extra richness and shine.