I have tried this recipe myself. Important is that if you plan on saving some sausages (putting in the freezer) you should use only dried herps/spices.
The cheese should also be a dry (parmesan). I used red dry wine and no peppers.
The fennel seed is the whole secret to this great italian sausage. The Grappa I drank after this meal....digestion etc.

Hot Italian Sausage

2 pounds pork butt, cubed
1 ounce salt
1/4 ounce black pepper
1/4 ounce fennel seed
1/2 ounce garlic powder
1/4 ounce paprika
1/2 ounce dried parsley
1/2 ounce crushed red pepper flakes
1/4 orange bell pepper, chopped
1/4 red bell pepper, chopped
1/4 yellow bell pepper, chopped
1 ounce cheese of choice
1 to 2 ounces wine, grappa, or brandy

1 yard pork or lamb casings