In spite of what the word may suggest, cream is not the key to creating “creamy” pasta dishes. That distinction belongs to pasta water, the starchy elixir with the power to thicken sauces and help them cling to and coat noodles with tenacity. Reserving a cup before draining the pasta an important step, but accidents happen, and sometimes all the water gets dumped down the drain before you realized what you’ve done.
If this happens, do not panic. There are two (2) ways you can create a pasta-water substitute.
How to make emergency pasta water if you accidentally dump yours down the drain
Starch is the thing that makes pasta water so valuable. Usually that starch makes its way from the noodles to the water while it’s cooking, but there are other ways you can create starchy water, and none of them involve buying or cooking extra spaghetti.
By adding semolina flour (the flour most commonly used to make pasta) to a pot of boiling water, you supercharge it with starch, effectively mimicking the effects of “real” pasta water.
In fact, you don’t even have to toss your pasta water to use this trick. I’ll often toss some semolina flour into my pasta pot with the noods to help make the water extra luscious and creamy, particularly if I’m making a dairy-free dish for my lactose-intolerant boyfriend. In that instance, I’ll go with a ratio of 1/2 cup of flour for 3 quarts of water, but you can scale it down to 2 teaspoons of flour for every cup of water make a single cup of emergency pasta water, if needed.
If you don’t have any semolina flour, you can use cornstarch instead. America’s Test Kitchen uses a ratio of 1/4 teaspoon of cornstarch in 1 cup of water. (Unlike flour, cornstarch is pure starch, so you don’t need as much of it.)
Whether you use flour or cornstarch, you’ll prepare the ersatz pasta water by whisking the powder into the water, and heating it in the microwave for a minute or two until it’s nice and hot. Splash into your sauce like you usually would, or use it to restore stiff, leftover pasta to its former glory.