My brother in law said cream in carbonara was a crime, then made it with cream at his own place in Omaha
He fed me the cream version at his house last weekend and my whole "purist" stance fell apart because it actually tasted better and didn't break, so now I'm wondering if anyone else has had a family member quietly disprove their own food rule right in front of them.
Kenji Lopez-Alt did a whole writeup years ago where he tested cream vs no cream and found the cream version holds up way better when you're cooking for a crowd. Something about the starch in the pasta water doing the work either way, but cream just gives you more room for error. Sounds like your brother in law knew what he was doing and just wanted to mess with you first. What did he say when you admitted it was good?