Preheat and Prepare the Dish: Begin by warming your oven to 375°F (190°C). Lightly coat a baking dish with a drizzle of olive oil, ensuring an even coating.

Cook the Pasta: Bring a large pot of water to a rolling boil, adding a pinch of salt. Cook the pasta shells just until tender but firm to the bite, following the package directions. Once done, drain the shells and run them under cold water to stop the cooking process. Set them aside to drain completely.

Make the Filling: Heat a generous splash of olive oil in a large pan over medium heat. Add the garlic and sauté for about a minute until it releases a fragrant aroma. Toss in the spinach, stirring until it wilts down. Once cooked, remove from heat and allow the mixture to cool slightly.

Stuff the Shells : Using a spoon, fill each pasta shell with the ricotta-spinach mixture. Arrange the stuffed shells in the prepared baking dish.

Assemble the Dish : Spread marinara sauce evenly over the stuffed shells. Sprinkle mozzarella cheese and the remaining Parmesan cheese on top.

Bake : Cover the dish with foil and bake for 20 minutes. Remove the foil and bake for an additional 10 minutes, or until the cheese is melted and bubbly.

Garnish and Serve : Remove from the oven and let rest for 5 minutes. Garnish with fresh basil or parsley before serving.