Creme Fraiche

You can use real creme fraiche if you can find it at a specialty store, but it's pretty expensive.  Make a reasonable and very tasty substitute by combining cream and buttermilk.  Here's the formula:

8 oz heavy cream
1 oz buttermilk

Whisk cream and buttermilk together thoroughly.  Cover, and let sit out for a few hours in a warm place until it has thickened somewhat.

Scale this recipe up as needed, keeping the same proportions. By volume, you want 2 tablespoons of buttermilk for each cup of heavy cream. I've made batches using up to 12 quarts of cream, so don't hesitate to up the recipe if you need to.

This could take up to 36 hours.  You will know it is ready when your shake the container and the contents sort of shimmy rather than ripple.  Refrigerate.  Your creme fraiche will continue to thicken in the fridge.  It should taste somewhat tangy and nutty.

Once ready, you can:

• whip it with some sugar (white, 10x or brown) a wee pinch of salt and flavorings (or you can make it savory by adding salt and herbs/spices).  When you whip it, it will thin out considerably and then whip up like whipping cream, so don't despair if you think it's not going well.
• use it in place of sour cream in recipes. Creme fraiche is great because, unlike sour cream, it doesn't curdle if it comes to a boil.
• substitute it for buttermilk, cream or sour cream in baking recipes. When subbing for heavy cream, add an additional 1/4 teaspoon of baking soda for each cup of creme fraiche to neutralize the acid in the creme fraiche and keep the recipe balanced.
• Whip it half and half with heavy cream to impart a subtle tang to your topping.

Creme fraiche is great for quenelling as a garnish for anything that you'd use whipped cream on.  It is a bit more sophisticated and complex a flavor than whipped cream (which is yummy as well, and will certainly do in a pinch).