A hot Italian sausage recipe made in the New World (America) is most often a fresh pork sausage that is seasoned with the distinct flavors of fennel and/or anise. It usually gets its heat from red pepper (commonly red pepper flakes).
In Italy, where there are lots of regional sausages, the term "Italian sausage" is really meaningless. Here in the "new world", we generally mean one or the other of two specific kinds..
The Italian sausage that most of us know comes 2 ways:
Sweet, which in its most basic form is seasoned with fennel, salt, and black pepper, and...
...Hot, which adds the red pepper flakes to the mix.
We're interested in the hot variety here.
HOW IT'S MADE
Italian sausage is usually made as a fresh sausage (no cure).
Pork shoulder (Boston butt) is the most common meat used for hot Italian sausage, and it needs to be 75 to 80% lean.
The meat is ground and the appropriate spices are added. The sausage is then portioned into bulk packages or stuffed into casings, and it either used immediately or frozen.
This is one of the easiest sausages for home sausage making, and there can be an endless variety of seasoning formulas.
Once you have found a recipe you like, be sure to experiment and fine tune it to your own family's taste.
Try your hot Italian sausage with fried peppers and onions on a sandwich roll or use it as a pizza topping. It's great in any number of ways. I even use it as a substitute for andouille in Cajun dishes.