The best sausage for this sort of easy pasta casserole are the fat links that
come five or six to a package. (Or, of course, honest-to-God Italian
sausages from an Italian butcher. But who would freeze those instead of
grilling them right up and snarfing them down?)
If you haven’t thought in advance to slice the sausages into 1-inch bits
before freezing them, don’t worry. Sausages are so full of fat that they slice
easily, even when frozen.