Step 1: Cook the rigatoni
Bring a large pot of salted water to a boil. Cook the rigatoni until al dente (about 1–2 minutes less than package instructions). Drain and set aside.

Step 2: Sauté the garlic and spinach
In a large skillet, heat olive oil over medium heat. Add minced garlic and sauté for 1 minute until fragrant. Add chopped spinach and cook until wilted (or warmed through if using frozen). Remove from heat and let cool slightly.

Step 3: Make the ricotta mixture
In a large mixing bowl, combine ricotta cheese, 1 cup of mozzarella, Parmesan, egg, salt, pepper, and oregano. Stir in the cooled spinach mixture until evenly combined.

Step 4: Mix pasta and sauce
In the same pot used for boiling pasta, toss cooked rigatoni with marinara sauce until well coated.

Step 5: Assemble the bake
Spread half of the sauced rigatoni in a 9×13 baking dish. Top with all of the ricotta-spinach mixture. Spread the remaining rigatoni on top. Sprinkle with the remaining 1 cup of mozzarella.

Step 6: Bake the dish
Cover with foil and bake at 375°F (190°C) for 25 minutes. Remove foil and bake an additional 10–15 minutes, until the top is golden and bubbling.

Step 7: Serve and enjoy
Let the pasta rest for 5–10 minutes before serving. Garnish with fresh basil or parsley if desired.