Prepare the Meat: Grind the pork, beef, and pork fatback through a medium-fine grinder. If using pre-ground meat, simply combine the three varieties in a large bowl.
Mix the Spices: In the same bowl, add the garlic, salt, black pepper, paprika, fennel seeds, and curing salt. If you're using wine, add it at this stage as well. Use your hands or a large spoon to thoroughly mix the ingredients, ensuring that everything is evenly incorporated.
Stuff the Casing: Soak the sausage casing in warm water to make it pliable. Stuff the mixture into the casing using a sausage stuffer, being careful to avoid air pockets. Tie off the ends tightly with butcher's twine.
Curing: Hang the stuffed salami in a cool, dry space with good airflow. The ideal curing environment is around 60-65°F (15-18°C) with humidity levels around 75-80%. Let the salami cure for at least 2-3 weeks, depending on your desired dryness and flavor intensity.
Slice and Enjoy: After curing, remove the salami from the casing, slice thinly, and serve. Enjoy it on its own, with cheese, or in a sandwich.