Add the chopped onions and garlic. Cook them until they are very soft. Stir in the crushed tomatoes and salt. Let the sauce simmer for twenty minutes.

Boil a large pot of salty water. Add the lasagna noodles to the water. Cook them until they are slightly firm. Drain them and set them aside carefully.

Mix the ricotta cheese and egg. Add the parsley and some salt. Stir it until the mix is smooth. This is your creamy middle layer.

Spread some meat sauce in the dish. Place a layer of noodles on top. Spread the ricotta mix over the noodles. Sprinkle some mozzarella and parmesan cheese.

Repeat these layers until you are done. The top layer should be cheese. Cover the dish with some foil. This prevents the top from burning.

Bake the lasagna in the hot oven. Remove the foil for the last minutes. Let it sit before you cut it. This helps the layers stay neat.