Step 1: Preheat your oven to 375°F (190°C). Brown the ground beef or Italian sausage in a large skillet over medium-high heat until no longer pink. Drain any excess fat.
Step 2: Stir the marinara sauce into the browned meat. Let it simmer gently for 5-10 minutes to allow the flavors to meld.
Step 3: In a separate medium bowl, combine the ricotta cheese, egg, 1/2 cup of grated Parmesan cheese, fresh parsley, salt, and black pepper. Mix until well combined.
Step 4: Spread a thin layer of the meat sauce (about 1 cup) on the bottom of a 9x13 inch baking dish.
Step 5: Arrange a single layer of no-boil lasagna noodles over the sauce. You may need to break some noodles to fit, ensuring the bottom is mostly covered.
Step 6: Spread half of the ricotta cheese mixture evenly over the noodles.
Step 7: Top the ricotta with about one-third of the remaining meat sauce.
Step 8: Sprinkle with a generous layer of shredded mozzarella cheese.
Step 9: Repeat the noodle, ricotta, meat sauce, and mozzarella layers once more.
Step 10: Place a final layer of noodles, then top with the remaining meat sauce. Finish with a final, thick layer of mozzarella and the remaining Parmesan cheese.
Step 11: Cover the baking dish tightly with aluminum foil. Bake for 30 minutes.
Step 12: Remove the foil and bake for an additional 15-20 minutes, or until the cheese is bubbly and golden brown. If desired, broil for 1-2 minutes for an extra crispy top (watch carefully!).
Step 13: Let the lasagna rest for 10-15 minutes before slicing and serving. This allows the layers to set for cleaner cuts.