Look, I know you are probably here for technology and not cooking tips from some doofus, but I had a little epiphany the other day and, well, it is my website, so I will share it here.
I was making a dish not too long ago — maybe hot and sour eggplant, but I am not sure — with a corn starch slurry. The corn starch is added to thicken the sauce, yes, but it also helps it adhere to the ingredients — eggplants in this case, but noodles in others.
A lot of cooks will tell you to use pasta water in the same way when you cook a sauced pasta. In a typical telling, you might set aside half a cup of the water the pasta is cooking in just before you strain it, then return the pasta to the pot with a sauce you prepared separately and then some of your pasta water. Tossing the starchy water with the sauce and pasta is supposed to help it bind better.
The little epiphany I had is to add some of the water back first, without the sauce, and let it reduce to a more concentrated state. Here is Albert Burneko in a recent article at about cacio e pepe over at Defector expressing the same sentiment:
What is happening all the while is, the pasta is absorbing a little bit of the moisture from that pasta water; at the same time, the heat is causing the rest of it to evaporate, slowly. As it does, it gradually reduces to a starchy goo, a sauce, which coats the pasta and makes it sticky and gives it a satin sheen. I promise this is happening while you are tossing, and I also promise that if it is not happening then it is because you and not I screwed up somehow.
I have tried this technique for a few different recipes and it is magical. Making this ultra-concentrated starch slurry does require you to undercook your pasta maybe a little more than you might usually for this technique, but the results are worth giving it a try. You get this super silky sauce that completely clings to whatever pasta you have made, in a way I have not found possible even when I cook my pasta in relatively small amounts of water to create a more concentrated cooking liquid. Reducing it later produces much nicer results — I think.