Slice the eggplant and onion thinly.
Sprinkle salt on the eggplant to remove moisture.
Heat olive oil in a pan and grill the eggplant on both sides.
Sauté the onion and minced garlic.
Add tomato sauce and simmer.
In an ovenproof dish, layer eggplant, tomato sauce, and ricotta cheese repeatedly.
Top with mozzarella cheese.
Bake in a preheated oven at 200°C for 25 minutes.