can you tell me what is half & half call for in the recipe

Irene, it is a cross between medium cream and milk, usually used by Americans for their coffee. You can approximate it (at least this is what i have always done) with half heavy cream and half whole milk. When a recipe's thickness/richness/butterfat content is flexible, Half and Half can replace other more fatty creams- as in soups and chowders.This is often done by cooks for health and weigght loss concerns.

Dairy cream with 12% fat