Creating this Roasted Veggie Lasagna is a rewarding process, broken down into manageable steps. Roasting the vegetables is key to maximizing flavor, and the layering process is simple and satisfying. Follow these instructions to create a lasagna that will impress everyone.

Step 1: Roasting the Vegetables to Perfection

1. Preheat Oven and Prepare Baking Sheet: Preheat your oven to 400°F (200°C). Line a large baking sheet with parchment paper for easy cleanup.
2. Combine Vegetables: In a large bowl, combine the diced eggplant, zucchini, bell peppers, red onion wedges, quartered mushrooms, halved cherry tomatoes, and minced garlic.
3. Season and Toss: Drizzle the vegetables with olive oil, sprinkle with dried Italian herbs, salt, and black pepper. Toss everything together until the vegetables are evenly coated.
4. Roast the Vegetables: Spread the vegetables in a single layer on the prepared baking sheet. Roast in the preheated oven for 25-30 minutes, or until the vegetables are tender and slightly caramelized, stirring halfway through. The roasting time may vary depending on your oven and the size of the vegetable pieces. You want them to be softened and have some browned edges, indicating concentrated flavor.
5. Set Aside: Once roasted, remove the vegetables from the oven and set aside to cool slightly. You can roughly chop the larger vegetable pieces if desired at this stage for easier layering.

Step 2: Simmering a Flavorful Tomato Sauce

1. Sauté Aromatics: In a large saucepan or Dutch oven, heat olive oil over medium heat. Add the finely chopped yellow onion and cook until softened and translucent, about 5 minutes. Add the minced garlic and cook for another minute until fragrant, being careful not to burn the garlic.
2. Build the Sauce: Pour in the crushed tomatoes and tomato paste. Stir well to combine. Add dried oregano, dried basil, sugar, salt, and black pepper.
3. Simmer and Develop Flavor: Bring the sauce to a simmer, then reduce the heat to low, cover, and let it simmer for at least 20 minutes, or up to 30 minutes, stirring occasionally. Simmering allows the flavors to meld together and deepen. The longer it simmers, the richer the sauce will become.
4. Taste and Adjust Seasoning: After simmering, taste the tomato sauce and adjust seasoning as needed. You might want to add more salt, pepper, sugar, or herbs to your preference.

Step 3: Preparing the Creamy Ricotta Layer

1. Combine Ricotta Ingredients: In a medium bowl, combine the ricotta cheese, grated Parmesan cheese, egg, chopped fresh parsley, salt, black pepper, and a pinch of nutmeg (if using).
2. Mix Until Smooth: Mix all the ingredients together until well combined and smooth. The ricotta mixture should be creamy and easily spreadable.

Step 4: Assembling the Lasagna Masterpiece

1. Preheat Oven and Prepare Baking Dish: Preheat your oven to 375°F (190°C). Lightly grease a 9×13 inch baking dish.
2. Layering Begins: Spread a thin layer of tomato sauce (about 1 cup) on the bottom of the prepared baking dish. This prevents the lasagna noodles from sticking and adds moisture to the bottom layer.
3. Noodle Layer: Arrange a layer of lasagna noodles over the sauce, slightly overlapping if necessary to fit the dish. If using regular lasagna noodles, ensure they are cooked al dente before layering.
4. Ricotta Layer: Spread half of the ricotta mixture evenly over the noodles.
5. Vegetable Layer: Top the ricotta layer with half of the roasted vegetables, spreading them evenly.
6. Mozzarella Layer: Sprinkle half of the shredded mozzarella cheese over the vegetables.
7. Repeat Layers: Repeat layers: sauce, noodles, remaining ricotta mixture, remaining roasted vegetables, and remaining mozzarella cheese.
8. Final Sauce and Cheese Topping: Top with a final layer of tomato sauce, spreading it evenly over the last layer of mozzarella. Sprinkle grated Parmesan cheese over the top for extra flavor and browning.

Step 5: Baking to Golden Brown Goodness

1. Cover and Bake: Cover the baking dish tightly with aluminum foil. Bake in the preheated oven for 30 minutes. Covering with foil prevents the top from browning too quickly and allows the lasagna to heat through and the noodles to soften.
2. Uncover and Brown: Remove the foil and continue to bake for another 20-25 minutes, or until the lasagna is bubbly, heated through, and the cheese is melted and golden brown on top. The baking time may vary slightly depending on your oven. You want to ensure the lasagna is heated through to the center.
3. Check for Doneness: To check if the lasagna is done, insert a knife into the center; it should come out hot.

Step 6: Rest and Serve

1. Rest Before Serving: Let the lasagna rest for at least 10-15 minutes before cutting and serving. This allows the lasagna to set, making it easier to slice and serve, and also prevents it from being too watery.
2. Garnish and Serve: Garnish with fresh basil leaves, if desired. Cut into squares and serve hot. Enjoy the delicious symphony of flavors and textures in your Roasted Veggie Lasagna!