HERE’S HOW is a series where we share the best useful tips from our cooking adventures. We’ll answer questions before you have them and illuminate food mysteries with a blend of science and legend. Today, we’re talking about improving your spaghetti endgame, so your pasta primavera tastes like it comes from the best Italian restaurant in the world.

If you know how to cook, chances are you can make a plate of pasta just fine. Yet there are a few secret tips that separate your average bowl of penne with tomato sauce from a lip-smackingly delicious dish of Fresh Rigatoni with Spicy Pork Ragu. Here are a few: use plenty of water, let it come to a rolling boil, salt the water adequately, and cook up a delicious sauce.

The most important trick–and the subject of today’s post–is what happens to the water after you’re done boiling the pasta.

Here’s the trick: when the pasta is 90 percent cooked, remove it from the pot. But don’t toss the water! Reserve at least 1 cup of the cooking water in a little bowl or cup. That water is no longer plain old H20. No, now it’s salty and starchy, a key ingredient in its own right. In the next step, as we add our pasta to the sauce in the neighboring pan, we also pour in a little bit of this water. This does two things. One, as your rigatoni or spaghetti finishes cooking in the pasta sauce plus water, each morsel will absorb more flavor from the sauce. And two, the starchiness of the pasta water will help thicken the sauce so it coats each bite of pasta instead of pooling in the bottom of your bowl.

You can watch this clever tip in action in our video about cooking pasta with heirloom tomatoes

P.S. The pasta shapes you have to know.