Trim the top and bottom of the eggplants. Slice the eggplants lengthwise to ¼" thick slices.
Place the eggplant slices on a baking sheet and generously sprinkle with salt on both sides. Let the eggplants sit and "sweat" for about 45 minutes. Then Pat dry them completely and brush with 1 ½ tablespoon olive oil on both sides.
Heat the oven to 400°F and once it's hot, bake the eggplants in the oven for 20 minutes.
Meanwhile, heat the remaining olive oil in a large pan and saute onion until golden.
Add in ground beef, salt, pepper, dried oregano and basil and cook it until brown, break it into pieces and you cook it.
Once the ground beef is browned, add in tomato sauce and crushed tomatoes. Cook for a few more minutes. Turn the heat off and set it aside.
In a large bowl, mix ricotta cheese with grated parmesan and egg. Set aside.
Now it's time to assemble your eggplant lasagna. Preheat the oven to 375°F and coat a baking dish with cooking spray. Start by spreading a thin layer of meat sauce at the bottom of the dish. Top with roasted eggplant slices, spread some ricotta cheese mix on the eggplant. add some meat sauce on top, and finish with a thin layer of mozzarella cheese. Repeat these steps until you run out of the beef sauce, eggplant sliced and ricotta mix.
Bake the eggplant lasagna in the oven for 40 minutes until the top gets all golden and bubbly.
Let the lasagna cool for 15 to 20 minutes before you slice it.