Heavy cream is defined in this country as cream with a fat content of between 30% and 40% (although we have seen it as high as 42%). You can often find it packaged as "heavy cream," but is also called whipping cream (or light whipping cream (with a fat content of 30% to 36%) or heavy whipping cream (36% to 40%)).

Half and half has a fat content of about 10.5%, and is definitely not what the recipe is calling for. Neither is canned evaporated milk, which is simply milk with about half the water removed, and a fat content of 8%.