Step 1: Heat the pork drippings or butter in a cast iron skillet. Add the onion and ham and cook over medium-high heat until browned, 3 minutes, stirring with a wooden spoon.
Step 2: Stir in the flour and cook for 30 seconds. Stir in the coffee and boil until reduced to 3/4 cup, 3 minutes, scraping the bottom of the pan with the wooden spoon to dissolve any burnt on meat juices.
Step 3: Stir in the tomato sauce, cream, Worcestershire, and sugar and simmer for 3 minutes. Add salt (you won’t need much—the ham is salty already) and pepper and additional sugar if desired to taste: the gravy should be highly seasoned.