And then you find a teeny container that seems to cost an awful lot.
Once you realize how easy it is to make your own, you'll probably never buy it again.
1/4 cup buttermilk
1 3/4 cups cream
Combine the milk and buttermilk. Stir to combine. I usually do this in a pint jar and start with the buttermilk and add the cream until it hits the pint mark. Oh, and make sure your buttermilk has active cultures. I think all of them do, but I figured I'd mention it just in case ...
Now comes the difficult part. Cover the jar (or wherever you've done the mixing) and let it sit on your counter - yes, at room temperature - overnight. Like, 8-10 hours. Overnight is a good idea because if you're sleeping you won't be poking your finger in it and wondering if it's okay or if milk on the counter overnight is a bad idea.
The next morning, refrigerate it. There you have it. Creme fraiche.
Whenever I have cream - heavy cream, whipping cream, whatever - left over from a recipe, I like to make some creme fraiche, even if I don't have a recipe planned for it. I can always find a use for it, even if it's just putting a little dollop on some berries.
But here's the thing. The creme fraiche will stay good longer than the cream it was made from. So it gives you a little extra time to figure out what you're going to do with it.