Have made this twice.
First time followed recipe adding some pepperoni with the italian sausage. Also used shredded vs. sliced cheese as what we keep on hand. Family said "it's a keeper", although seasoning a bit subdued for our tastes. I'm sure that will vary with the sausage you use as no other seasonings in the recipe.
Second time I made veggie version with the following modifications:
... used 1-3/4 cup favorite pasta sauce for the canned tomatoes (kept the tomato paste for thickening
... added 1 tsp garlic powder, 1 tsp oregano, 1/2 tsp basil to up the seasonings
... replaced sausage with 1/2 green pepper, 1/2 med. onion, 4 oz. mushrooms, 1/2 can medium black olives, and two roma tomatos. Coarse chop onion/pepper, mushroom/tomato thick slices, but left olives whole. Light saute on onion and green pepper before adding sauces, but just added mushroom, tomato, and olive to sauce just to heat.
Veggie version came out great. Liked overall taste better than first ti