Preheat the oven to 425°F with a rack placed in the center of the oven.
Bring a deep sided skillet (or pot) of water to a rolling boil. Salt generously and drop in the eggplant. Boil the eggplant for 4 minutes, then remove with tongs or a slotted spoon and drain between paper towels. Press to remove excess moistures.
In the same skillet, drop in the lasagna and boil for about 6-8 minutes or until nearly al dente. Drain and set aside.
Heat the olive oil in the same skillet over medium heat. If using meatless crumbles, add it to the pan, and let it lightly brown, stirring occasionally. Add the marinara sauce to the pan and let it come to a bubble. Season to taste with salt and pepper.
Stir in the crumbled tofu and add the eggplant and lasagna noodles, making sure the noodles are fully coated in the sauce and spread evenly in the pan.
Top the skillet with mozzarella cheese and parmesan cheese, and place in the oven to bake for about 10 minutes, or until the skillet lasagna is bubbling and the cheese is melted.
Remove from the oven, garnish with parsley and serve immediately.
To make this a vegan skillet lasagna, simply substitute the mozzarella and parmesan cheeses with your favorite vegan cheeses!