I understand that eggs contain proteins that change from liquid to solid when cooked which gives the custard it's texture. How does sour cream accomplish this?
what custard recipe have you seen that has these 2 without eggs?
I'm going to hazard a guess that this recipe has some sort of acid (eg. lemon juice, vinegar, etc). What the acid does is curdle the dairy and thickens it. I don't think the sour cream is totally responsible for the texture, though most sour cream has a thickener in it (read the label, look for things like pectin, gelatin, carrageenan etc).
Actually, this came from a popular online recipe for key lime pie. It must have been the key lime juice that thickened the milk. Interesting. Thanks for the reply.
there is also a ginger, milk and sugar pudding that is a traditional chinese dessert. it is fascinating to see it made....look for it on youtube. i have no idea of the chemical reaction that occurs.
There's an enzyme in the ginger that thickens (curdles) the milk.