In a 3-quart saucepan, cook the macaroni in boiling water until tender. Drain well. (If you decide to use Rotini pasta in place of the elbow macaroni, be sure to use at least 2-1/2 cups, and cook the pasta for 10 minutes.)
Add the drained macaroni back into the pan, then add in the mayonnaise, stewed tomatoes, a 3/4 cup of shredded mozzarella, and the Italian seasoning; stir the ingredients.
Pour the mixture into a 2-quart baking dish.
Sprinkle the remaining 1/2 cup of shredded mozzarella over the casserole, and bake uncovered in the oven for 20 minutes.
Before serving, I lightly sprinkle a bit of dried parsley flakes on top the casserole. Also, you'll notice this recipe doesn't state to add any salt or pepper. I add those spices to my plate when seated at the table.
*Note: When making this casserole, you can substitute another type of pasta for the macaroni. Sometimes I'll use Radiatore Pasta, or even Rotini. (I do however, cook the Radiatore Pasta for 10 minutes.) I have also prepared this meatless casserole using a four cheese blend, instead of the mozzarella cheese. Surprisingly it turned out to be quite good. (See additional photos which I added.) One more thing, you can also substitute a can of diced tomatoes (which has basil, garlic & oregano in it), for the stewed tomatoes.