Prepare the eggplant and potatoes. Slice the eggplant into 1 cm (½-inch) thick rounds. Sprinkle with salt on both sides and let stand 30 minutes.
While the eggplant is waiting, wash and chop the chard, onion and potatoes. Preheat oven to 200 °C (390 °F), convection mode.
Blot the eggplant dry. Brush both sides of the eggplant and potatoes with 3 tbsp oil. Sprinkle some salt on the potatoes. Place the eggplant and potato rounds on two large baking sheets and bake 25 minutes. Continue preparing the sauces (steps 4 & 5) while the eggplant and potato bake.
Prepare the chard-tomato sauce. In a large pot over medium heat, heat 2 tbsp oil. Add the onion and garlic and cook about 3 minutes, stirring often. Add the chard leaves and ½ tsp salt. Cook uncovered until just wilted, about 3 minutes. Add the ½ cup wine, stir, and let cook 1 minute. Add the tomatoes, 2 tbsp tomato paste, bay leaf, cinnamon stick, pepper, and ¾ tsp salt (if your canned tomatoes contain salt, reduce salt to taste). Cook uncovered about 10 minutes or until thick. Stir in 30 g ricotta. Set aside.
Prepare the béchamel sauce. Melt the butter over medium low heat. Whisk in the flour. Let cook about 1 minute, whisking frequently. Slowly add in the milk, whisking constantly. Bring to a boil for about 30 seconds to thicken, then off heat. Whisk in remaining ricotta, ¼ tsp salt, and a pinch of nutmeg. Whisk in the egg yolk, being sure to whisk it in immediately after adding.
Keep the oven heated to 180 °C (350 °F).
Assemble. Butter a large (9x13 inch) baking dish. Place the potatoes in a single layer, then layer on half the eggplant. Next add all of the chard-tomato sauce, then the rest of the eggplant. Top with the ricotta béchamel sauce. Smooth out the sauce with a spoon. Finally sprinkle with the grated cheeses.
Bake at 180 °C (350 °F) for 50 minutes. Let cool slightly before serving, and enjoy!