Follow these steps carefully for a perfect Spinach Ricotta Pasta Bake every time:

1. Preheat Oven & Cook Pasta: Preheat your oven to 375°F (190°C). Bring a large pot of generously salted water to a rolling boil. Add the pasta and cook according to package directions, but slightly undercook it by 1-2 minutes (it should be al dente). It will finish cooking in the oven. Drain the pasta well and set aside. Rinsing is generally not necessary.
2. Sauté Aromatics & Spinach: While the pasta cooks, heat the olive oil in a large skillet or Dutch oven over medium heat. Add the minced garlic and sauté for about 30-60 seconds until fragrant – be careful not to burn it. Add the fresh spinach in batches, stirring until it wilts down significantly. If using frozen spinach (thawed and squeezed dry), simply add it to the skillet and heat through with the garlic for a couple of minutes. Cook until most of the moisture has evaporated. Remove from heat.
3. Prepare Ricotta Mixture: In a medium-sized bowl, combine the whole milk ricotta cheese, the large egg, 1/4 cup of the grated Parmesan cheese, the freshly grated nutmeg, and a generous pinch of salt and black pepper (about 1/2 teaspoon salt and 1/4 teaspoon pepper, adjust to taste). Stir everything together until well combined and smooth.
4. Combine Ricotta and Spinach: Add the cooked spinach and garlic mixture from the skillet to the ricotta mixture in the bowl. Stir well to ensure the spinach is evenly distributed throughout the creamy ricotta filling. Taste and adjust seasoning if needed.
5. Combine Pasta and Sauce: In the large pot you cooked the pasta in (or a large mixing bowl), combine the drained, al dente pasta with about 2 cups (16 ounces) of the marinara sauce. Gently toss to coat the pasta evenly. You want enough sauce to lightly coat every piece, but not so much that it becomes soupy.
6. Assemble the Pasta Bake: Lightly grease a 9×13 inch (or similar size) baking dish. Spread a thin layer (about 1/2 cup) of the remaining marinara sauce on the bottom of the dish. This prevents the pasta from sticking.
7. Layer the Ingredients: Add about half of the pasta mixture over the sauce layer in the baking dish. Dollop about half of the spinach-ricotta mixture evenly over the pasta layer. You can spread it gently or leave it in dollops for pockets of creaminess. Sprinkle about half of the shredded mozzarella cheese (4 ounces) over the ricotta layer.
8. Repeat Layers: Add the remaining pasta mixture over the mozzarella. Dollop the remaining spinach-ricotta mixture evenly over the pasta. Pour or spread the last 1/2 cup of marinara sauce over the top (you can add a little more if you like it saucier).
9. Final Topping: Sprinkle the remaining 4 ounces of shredded mozzarella cheese and the remaining 1/4 cup of grated Parmesan cheese evenly over the top layer.
10. Bake: Cover the baking dish loosely with aluminum foil. This prevents the top from browning too quickly and helps the inside heat through evenly. Bake in the preheated oven for 20 minutes.
11. Brown the Top: Carefully remove the aluminum foil. Continue baking for another 15-25 minutes, or until the sauce is bubbly around the edges and the cheese on top is melted, golden brown, and slightly crusty. The internal temperature should reach at least 165°F (74°C).
12. Rest: Once baked, remove the pasta bake from the oven and let it rest for at least 10-15 minutes before serving. This allows the cheese and sauce to set slightly, making it easier to cut and serve, and prevents scorching mouths!
13. Garnish and Serve: Sprinkle with optional chopped fresh basil or parsley just before serving for a pop of colour and freshness.