Some brands offer sausage meat without the casing. I'm able to find it in a variety of flavors (salt and pepper, mild italian etc). Look beside the other sausages in the meat section. It will look similar to a package of ground beef. If you don't have it locally, you can use regular sausages by cutting off the casing and cooking what's inside. 1 cup of ground sausage meat will equal 1-2 sausages depending on size.