Creating Spinach and Mushroom White Lasagna can be a fun and straightforward process if you follow these steps:

1. Preheat the Oven: Start by preheating your oven to 375°F (190°C).
2. Cook the Noodles: Boil the lasagna noodles according to the package instructions. Drain and set aside.
3. Sauté the Vegetables: In a large skillet, heat olive oil over medium heat. Add minced garlic and sliced mushrooms, cooking until the mushrooms have released their moisture. Stir in chopped spinach and cook until wilted. Season with salt, pepper, and Italian seasoning.
4. Prepare the Cheese Mixture: In a bowl, combine ricotta cheese, 1 cup of mozzarella, and ½ cup of Parmesan cheese. Mix well and set aside.
5. Assemble the Lasagna: In a baking dish, spread a layer of white sauce on the bottom, place three lasagna noodles, half of the vegetable mixture, then half of the cheese mixture. Repeat the layers, ending with noodles topped with white sauce and remaining mozzarella and Parmesan cheese.
6. Bake: Cover the baking dish with aluminum foil and bake for 30 minutes. Remove the foil and bake for an additional 15 minutes until the top is golden and bubbly.
7. Cool Down: Once cooked, take the lasagna out of the oven and let it cool for about 15 minutes before slicing.
8. Serve: Serve warm with a fresh garden salad on the side or garlic bread.

These straightforward steps will guide you through the process of making this wonderful Spinach and Mushroom White Lasagna with ease.