Start by getting your oven preheated to 375°F.
Take a large frying pan and cook the ground beef or Italian sausage until it is fully cooked. Get rid of any extra oil by draining it.
Include diced onion and minced garlic in the pan and continue cooking until the onions turn a translucent color.
Mix in crushed tomatoes, tomato paste, basil, oregano, salt, and pepper to the pan and let it simmer for 10 minutes.
Cook the lasagna noodles as per the instructions on the packaging and drain.
In a separate bowl, blend together the ricotta cheese and egg.
Using a spatula, evenly distribute a light layer of meat sauce in a 9x13-inch baking pan.
Arrange three previously cooked lasagna noodles on top of the meat sauce.
Layer half of the blended ricotta cheese on top of the noodles, and then sprinkle a cup of shredded mozzarella cheese over it.
Repeat the layering process with another three noodles, the remaining ricotta mixture, and another 1 cup of mozzarella cheese.
Place the final three noodles on top, followed by pouring the remaining meat sauce over them.
Distribute the final amount of mozzarella cheese and grated Parmesan cheese evenly over the dish.
Encase the pan with aluminum foil and let it bake for a duration of 25 minutes.
After 25 minutes, remove the foil and continue baking for an additional 25-30 minutes until the cheese is melted and golden in color.