Is there any way to make sour milk from half and half? I'm out of milk!

You could have used the half-and-half, too. You would have a slightly higher fat content, but I don't think that would cause a problem with results.

I forgot I had raw milk frozen in cubes in the freezer - yeah! Here's how to make sour milk if anyone wants to know: Using a glass measuring cup, put in a tablespoon of lemon juice or white vinegar and add milk to equal a cup. Let that stand around for 15-20 minutes or so til the milk begins to curdle. Presto! Sour milk.