1️⃣ Prepare the Mushroom & Spinach Filling

• Heat olive oil in a large skillet over medium heat.
• Add onions and garlic and sauté until fragrant.
• Stir in mushrooms and cook until soft and golden brown.
• Add spinach and cook until wilted (if using fresh) or heated through (if using frozen).
• Season with salt and black pepper to taste. Set aside.

📌 Pro Tip: Drain excess moisture to prevent a watery lasagna.

2️⃣ Mix the Ricotta Cheese Layer

• In a bowl, mix ricotta cheese, egg, nutmeg, salt, and pepper.
• Stir until smooth and creamy.

3️⃣ Assemble the Lasagna

• Preheat oven to 375°F (190°C).
• Spread 1 cup of marinara sauce in the bottom of a 9×13-inch baking dish.
• Layer 3 lasagna noodles over the sauce.
• Spread ⅓ of the ricotta mixture, then ⅓ of the spinach-mushroom filling, and sprinkle mozzarella cheese on top.
• Repeat until all layers are complete, finishing with cheese on top.

📌 Pro Tip: For an extra cheesy top, mix Parmesan with mozzarella for better browning!

4️⃣ Bake Until Golden & Bubbling

• Cover with foil and bake for 30 minutes.
• Remove foil and bake 15 more minutes until the cheese is golden brown and bubbling.
• Let the lasagna rest for 10 minutes before slicing.

📌 Pro Tip: Letting the lasagna cool slightly before slicing ensures clean layers!