Expired heavy cream is safe to eat as long as it has not actually gone bad.
You won't get sick from expired heavy cream as long as the expired heavy cream does not smell bad or has mold or a bad taste to it.
Heavy cream is usually good in the refrigerator for up to a month without going bad.
Just because the heavy cream has expired doesn't mean that it's bad or unsafe to eat as long as it smells good, has no mold in it etc.
If it smells sour or has mold in it then throw the heavy cream out.
If you do eat bad heavy cream that has expired you'll experience symptoms such as vomiting, diarrhea, stomach cramps etc.
If you don't think the expired heavy cream is still good then just throw it out and do not risk your health.
The meaning of tempered heavy cream is when you warm the cream and add the warm cream and add hot broth to the cream.
Tempering the cream means to warm the cream up so you would warm the heavy cream up and then slowly add some hot broth to the cream to make tempered heavy cream for your recipe.
You can also warm or temper your heavy cream using the hot broth by taking half a cup of the hot broth and slowly add your heavy cream to it.
Be sure to stir the heavy cream constantly while adding the hot broth to it.
Once you do that then you have tempered your heavy cream.
The term tempering in recipes is usually called for in recipes when making things such as ice cream, custards, cream soups etc.
The technique of tempering the cream or other mixture is to add a small amount of the hot liquid to the cold ingredient.
Then you add the tempered mixture into the rest of the hot liquid.
That is tempering.