Can I use buttermilk powder to make creme fraiche?

It might work, but you’d probably want to re-constitute it in some water or milk before mixing it in with the cream. I believe that creme fraiche made this way has to sit for a while to thicken up, one internet source says it has to sit for at least 8 hours. If you’re going to wait for 8 hours, you could find the time to go buy some buttermilk?

The other way I’ve made Creme Fraiche is using a mix of sour cream and cream. I don’t remember the proportions we used, but just slowly mix in cream into the sour cream until it’s at a good consistency. It’s ready instantly, and it’s pretty darn yummy, although since I’ve never had the real thing, I don’t know how it matches up. What are you planning on eating it with?

Yes, you can use powdered buttermilk in creme fraiche—don’t use as much powdered as you would use regular buttermilk, and dissolve it in a little of the warmed cream before adding to the rest of the cream. I’d say maybe use half to a third as much buttermilk powder as regular buttermilk. It might take a bit of experimentation.