My friend Tifanie let me in on this little secret! All I can say is this is awesome!! We had baked potatoes the other night with this and my husband was in heaven.
1 liter cream
3 tbsp white vinegar
Add the vinegar to the cream and stir. Leave out at room temperature overnight.
The cream will thicken within a few hours. Pour off some of the excess whey. Store in the refrigerator for two weeks.
If you want it thicker you can strain it in a fine mesh strainer or with cheesecloth. Personally I thought it was just fine after pouring off the excess liquid.
I thought I had a picture of the end product, but it looks like I forgot to take one so I'll have to update this post when I take one.