A quart of milk has gone sour. What's a good way to use it?

Yes, I bought it in advance of need and didn’t use up the old one fast enough. I hate to just pour it out, but I don’t know how to use it well.

Would it ruin recipes that call for milk? What about using it for things like Kraft mac & cheese?

I’m not leaving the house this week, or at least not to shop anywhere, so this is what I’ve got.

Thank you.