Preheat oven to 350 degrees Fahrenheit.
Butter a 9 by 13 inch clear glass baking dish. Cut the remaining butter in chunks and dab across the dish. The heat from the pasta will melt this.
Add 4-5 quarts of water to a pot. Bring to a boil. Add salt and olive oil to the water.
Add pasta to the water. Boil for about 6-7 minutes, or until "al dente" (Italian for "to the teeth" or firm). You want the pasta a little under cooked because you will bake it.
Drain the pasta, then add it to the buttered baking dish.
Pour the pasta sauce over the pasta.
Spread the shredded mozzarella cheese over the dish. Drizzle the heavy cream over the shredded mozzarella. This will keep the cheese from drying out during baking.
Rip small chunks of the fresh mozzarella and arrange on top of the dish.
Bake in the preheated oven for 30 minutes. Enjoy the warm cheesy goodness.
I use a clear glass baking dish for this recipe. It adds to the presentation and is easy to clean after.