Sprinkle eggplant slices with salt. Set aside for 10 minutes so it can draw out moisture. Pat dry with a paper towel and lightly brush with 1tbsp olive oil.
Place a grill over medium heat. Grill the eggplant slices for around 2 minutes per side. Remove from fire and set aside. (You can do this in a skillet if you don't want to use a grill.)
In a saucepan over medium heat, heat olive oil. Cook onions until transparent, add minced garlic and cook until fragrant. Mix in crushed tomatoes, oregano and basil. Simmer for 10 minutes and remove from heat
Preheat oven to 350 degrees.
Assemble the lasagna. Coat the bottom of a baking pan with tomato sauce, top it with eggplant slices and a mix of ricotta, mozzarella and parmesan cheese. Add more tomato sauce and another layer of eggplant. Repeat the process ending with cheese.
Take lasagna to oven and bake for 20 minutes or until bubbly.
Notes
To freeze for meal prep, assemble the ingredients in aluminum pans, wrap with saran wrap, and put in the freezer. They'll be good for several months.