Start by heating olive oil in a saucepan and sautéing garlic until fragrant. Add cream, vegetable broth, and a bit of parmesan, then simmer gently.
In a skillet, quickly sauté spinach until wilted and set aside. Then cook mushrooms until golden and slightly crispy on the edges. This step enhances their flavor and prevents the casserole from becoming watery.
Spread a thin layer of sauce at the bottom of your baking dish. Add ravioli in a single layer, followed by spinach, mushrooms, sauce, and cheese. Repeat the layers to build a rich and even casserole.
Cover the dish with foil and bake in a preheated oven at 400°F (200°C). After about 20 minutes, remove the foil and bake briefly to get a golden, bubbly cheese topping.
Once baked, sprinkle parsley and chili flakes on top for extra flavor. Let it cool slightly before serving so the layers set nicely and are easier to portion.