Liaison is a mixture of egg yolks and cream/yogurt, that is used to thicken soups or sauces. You will see a lot of recipes on this blog, that use this technique. At home we like to use liaison for almost all the soups we make. The benefits are: slightly thicker soup, richness and mouth feel. Try Chicken Gizzard Soup , that uses liaison to see how tasty and rich it is.
You should remember
, that egg will curdle, so when you add the mixture of egg yolks and cream/yogurt to your soup or sauce, their temperature should never be higher than 180-185 F and about 83 C.
, which of course depends on how thick you want your soup or sauce, is 16 x 1 x 2 for sauces and 80 x 1 x 2 for soups. So for every 16 ounces (or one pint) of sauce, you will need 1 egg yolk and 2 ounces of cream/yogurt and every 80 ounces (or five pint) of soup, you will need 1 egg yolk and 2 ounces of cream/yogurt .
To incorporating a liaison
into a sauce or soup put yolk from 1 egg and add 2-3 tablespoons half and half or 2-3 tablespoons of homemade yogurt in a separate bowl. Now slowly add some of your hot sauce to your cream and yolk mixture until the temperature of your mixture is close to that of your sauce/soup, whisking constantly. That’s called to temper the eggs or you risk to end up with cooked eggs in your sauce, if you just combine the two mixtures. Add the entire mixture back into your original sauce/soup. If you need to cook your sauce or soup more, place in a double boiler to prevent the mixture from reaching a temperature higher than 180°F (80°C).