In a large skillet over medium heat, brown the ground beef until well-cooked, approximately 7–10 minutes. Add the diced onions, grated carrot, and sliced celery, cooking until onions become translucent, about 5 minutes. Stir in the drained mushrooms, pasta sauce, salt, black pepper, and oregano. Let it simmer for 10 minutes, then set aside to cool slightly.

Soak the lasagna noodles in boiling water for about 4 minutes. Drain and hang on a rack or parchment paper to prevent sticking.

In a mixing bowl, combine ricotta cheese, egg, grated Parmesan cheese, and dried parsley. Mix until smooth and creamy.

In a baking dish, layer meat sauce, followed by 3 noodles. Spread half of the ricotta filling over noodles, then sprinkle with 4 oz of shredded mozzarella. Repeat layers, finishing with a final layer of meat sauce and 8 oz of mozzarella on top.

Cover the lasagna tightly with heavy-duty foil. Label with the date and name. Can be stored in the freezer for up to 3 months.

When ready to enjoy, thaw lasagna in the fridge overnight. Preheat oven to 350°F and bake uncovered for about 1 hour, until bubbly and golden.