Step 1: Cook the Meat Sauce : Heat olive oil in a skillet. Sauté onion until soft, add garlic, then brown the pork. Stir in crushed tomatoes, tomato paste, oregano, basil, red pepper flakes, salt, and pepper. Simmer 15–20 minutes.
Step 2: Prepare the Cheese Mixture : In a bowl, combine ricotta, ½ cup Parmesan, egg, and chopped spinach. Mix well.
Step 3: Layer the Lasagna : Spread a thin layer of meat sauce in the baking dish. Layer noodles, ricotta-spinach mixture, meat sauce, and mozzarella. Repeat layers two more times, ending with cheese.
Step 4: Bake the Lasagna : Cover with foil and bake at 375°F for 30 minutes. Remove foil and bake 15–20 more minutes until cheese is bubbly and golden.
Step 5: Rest and Serve : Allow lasagna to rest for 10 minutes before slicing. Garnish with fresh parsley or basil.