2 Cups Heavy Whipping Cream
3 Tablespoons buttermilk
Pour the cream in a non reactive bowl or dish, I use a clear glass casserole dish. Then stir in the buttermilk and cover it with a towel. It needs to get air but doesn't need to be disturbed so a towel works perfect.
Leave it on your counter or table at room temperature 70-75 for 16-24 hours. Mine usually takes about 16 at 73 degrees. Depends on temp and humidity. It has taken as long as 30, but that was my first couple of tries and the temp was the problem.
After about 12 you can check it. I use a clear glass dish so I can just gently shake it to see if it's still liquid. If it is leave it alone for a couple of hours and check it again.
When it's done stir it real good and refrigerate. It'll stay good for about a week.
I start it at night after I'm done in the kitchen and it's usually done by noon or so.
May Seem like a pain but it's not at all. After you do it a couple of times and get it down, it's so simple and worth it.