Begin by preheating your oven to 375°F (190°C). This step is crucial, as a preheated oven ensures your pasta dish will cook evenly and achieve that perfect crispy top.

In a large pot of salted boiling water, cook the penne pasta according to the package's instructions, usually around 8-10 minutes, until al dente. Don’t forget to stir occasionally to prevent sticking! Once cooked, drain the pasta well and set it aside.

In a mixing bowl (or even in the now-empty pot), combine your marinara sauce, ricotta cheese, sour cream, minced garlic, and Italian seasoning. Stir this mixture until everything is well blended. The combo of flavors here is just fabulous and will envelop the pasta in creamy deliciousness.

Now for the fun part! Gently fold the cooked penne into the saucy mixture. Make sure every noodle is well coated. Then, stir in 2 cups of shredded mozzarella cheese to the mix for that gooey stretch in every bite.

Transfer this creamy pasta mixture into a 9x13-inch baking dish. Spread it out evenly. Your dish should be starting to look tasty already!

Sprinkle the remaining 2 cups of shredded mozzarella and the grated Parmesan cheese evenly on top. This will create a delightful crust that is the crème de la crème of this baked dish.

Slide your baking dish into the oven and bake for 15-25 minutes, or until everything is bubbling and the cheese on top has melted and turned golden. The delicious scent wafting through the kitchen will make everyone eager to dig in!

Once out of the oven, let it cool for a few minutes before serving. Trust me; if you can resist diving right in for a couple of minutes, it will be worth the wait. You can store any leftovers in an airtight container for up to three days—if, of course, you have any left!