Actually, hamburger gravy has many types (most fairly healthy) and use
little or none of the actual fat from the cooked ground beef.
Standard gravy rule of thumb:
2TB fat base (can be any fat but not oil)
4-5TB flour
Melt fat and slowly incorporate flour to a paste
2-3c broth (can be any type including bullion but some bullions are too
salty)
Common fats used (some area dependent):
Beef (may be ground fat 'drippings')
Chicken (other poultry too like duck or goose)
Pork (sausage, bacon, etc.)
Common additions:
Worstershire sauce
Kitchen Bouquet
Salt and Pepper
Ketchup
Port
Basics are to make a slow paste of the fat and flour then slowly add
liquid and seasonings of choice then wisk it until thickened. Takes
about 5 minutes.
In traditional southern or early American style, the fat was anything
you had. Navy style, things got healthier but used to be no fat that
was made from cooking and could be used, was used. Our infamous
'chipped beef and gravy' comes from that era. Started with salt beef
or salt pork or dried beef for the Navy.