First, put on a large pot of water to boil. Add about 2 tablespoons salt to the water. Bring to a rolling boil. Add pasta in while you are frying the sausage, and cook to 1 minute less than the time suggested on the package. The pasta will cook more in the oven.
While pasta is cooking, heat up a cast iron skillet and fry the Italian sausage. Drain the grease out by using the back of a spatula to hold meat in. Then, using a few paper towels, pat the meat and wipe any excess grease out of the pan.
Drain the pasta, reserving at least 1 cup of liquid. Add the pasta into the pan with the sausage.
Now, toss in the red sauce and the spinach and mix just enough to evenly distribute the spinach. At this point, if the mixture seems dry, add a bit of the pasta water. Depending on red sauces, you may or may not need to.
Drain the liquid from the mozzarella balls and place them over the top of the bake, gently pressing them into the pasta.
With a small ice cream scoop or spoon, dot the ricotta over the top. Smooth this out to form a bit of a covering. (don’t worry if it is not pretty, because you will be covering it with mozzarella later!) Sprinkle the Italian Seasoning and granulated garlic over the top of the pasta!
Now it is time to cover with foil and place in a 350 F degree oven. Set the timer for 15 minutes, and then spin the pan. Set for another 15 minutes. Watch for bubbling. All ovens vary, so it could take another 10 minutes.
Once it it is bubbling, pull the pan out of the oven and cover with shredded mozzarella cheese. Return pan to oven and bake until bubbly and cheese is starting to brown. Pull pan out of oven and let set up for about 10 minutes. Sprinkle with parsley, and serve.