Follow these steps carefully to build layers of flavor, resulting in a perfectly creamy and delicious pasta bake every time. The process involves cooking the pasta, creating the sauce, and then combining everything for the final bake.

Step 1: Prepare Your Workstation and Cook the Pasta

1. Preheat and Prep: Preheat your oven to 375°F (190°C). Lightly grease a 9×13-inch (or equivalent 3-quart) baking dish with butter or non-stick spray.
2. Boil Water: Bring a large pot of water to a rolling boil. Add a generous tablespoon of salt. Salting the water is essential for seasoning the pasta from the inside out.
3. Cook Pasta: Add your chosen pasta to the boiling water and cook according to package directions, but be sure to undercook it by about 2 minutes. You want it to be al dente (firm to the bite). The pasta will continue to cook in the oven, and this step prevents it from becoming mushy.
4. Reserve Pasta Water: Before draining the pasta, reserve about 1 cup of the starchy pasta water. This water is “liquid gold” and can be used to thin out your sauce later if needed.
5. Drain and Set Aside: Drain the pasta and return it to the pot. Drizzle with 1 tablespoon of olive oil and toss to coat. This prevents the pasta from clumping together while you make the sauce.

Step 2: Create the Creamy Spinach Artichoke Sauce

1. Sauté Aromatics: In a large skillet or Dutch oven, melt the 2 tablespoons of unsalted butter over medium heat. Once shimmering, add the minced garlic and cook for about 30-60 seconds until it becomes fragrant. Be very careful not to let the garlic brown or burn, as it will turn bitter.
2. Build the Creamy Base: Reduce the heat to low. Add the softened cream cheese, heavy cream, and vegetable broth to the skillet. Whisk continuously until the cream cheese has completely melted and the sauce is smooth and uniform. This may take a few minutes; be patient and keep whisking to avoid lumps.
3. Melt in the Cheese: Gradually stir in the 1 cup of freshly grated Parmesan cheese until it’s fully melted and incorporated into the sauce.
4. Season the Sauce: Season the sauce with the black pepper and freshly grated nutmeg. Stir to combine. Give it a taste and add a pinch of salt if needed (the Parmesan and vegetable broth already add saltiness, so taste first).
5. Incorporate Spinach and Artichokes: Add the thoroughly squeezed-dry spinach and the chopped artichoke hearts to the sauce. Stir until they are evenly distributed throughout the creamy mixture. Let the sauce gently simmer for another 2-3 minutes for the flavors to meld.

Step 3: Assemble and Bake the Casserole

1. Combine Pasta and Sauce: Pour the creamy spinach artichoke sauce over the cooked pasta in the large pot. Gently stir everything together until every piece of pasta is generously coated in the luscious sauce.
2. Transfer to Baking Dish: Pour the pasta mixture into your prepared 9×13-inch baking dish. Use a spatula to spread it into an even layer.
3. Add the Cheesy Topping: Sprinkle the 2 cups of shredded mozzarella cheese evenly over the top of the pasta. If using, add the optional Gruyère or Provolone cheese as well for extra flavor.
4. Bake to Perfection: Place the baking dish in the preheated oven. Bake for 20-25 minutes, or until the cheese is completely melted and the sauce is bubbling around the edges.
5. Golden-Brown Finish (Optional but Recommended): For a beautifully browned and crispy top, switch the oven to the broiler setting for the last 2-3 minutes of cooking. Watch it very closely, as the cheese can go from golden to burnt in a matter of seconds.
6. Rest and Garnish: Remove the pasta bake from the oven and let it rest on a wire rack for at least 10-15 minutes. This crucial step allows the sauce to set and thicken, making it easier to serve and preventing it from being too runny. Garnish with freshly chopped parsley before serving.