How to make your own crème fraîche from Bon AppetitCombine 2 tablespoons of buttermilk with 1 cup of whipping cream in a glass container. Cover and let it sit at room temperature (about 70ºF) for 8 to 24 hours. Don't despair if your cream doesn't thicken after 22 hours; sometimes it happens nearly all at once. When it has thickened, stir well and refrigerate up to 10 days.
Today I am making a lower calorie version using half and half instead of cream and using 1 1/2 t. of buttermilk powder instead of buttermilk. To mix you can shake or slightly warm it but I threw mine in the blender for a good mixing. I had to break up those pebbles of buttermilk powder.