I made the "ad hoc at home" beef stroganoff last night and it was absolutely delicious!
So of course I spent all morning thinking about the leftovers I was going to have for lunch today. When I uncovered the bowl in the fridge I found this solid ball of noodles, mushrooms, and beef all held together by a cement like cream sauce where my silky beef stroganoff had been the night before. This probably isn't news to most of you but it surprised newbie me.
I remembered that you're supposed to use reserve cooking liquid to thin out sauces if they set too much, but of course I didn't save any of that. But...I also remembered reading about how it is important to wash rice to rinse off all the excess starch. So I put a teaspoon of rice in a cup of water and within second it was too cloudy to see the bottom.
I used that starchy rice water to reconstitute my pasta and it turned out even silkier and richer than it was the night before.
Anyways hopefully this is useful to at least some people.