Start with the vegetables: Slice the potatoes into 1/2-inch (about 1 cm) rounds and arrange them on a baking sheet. Drizzle with a little olive oil and sprinkle with salt. Bake in a preheated oven at 400°F (200°C) on convection for 20 minutes until softened. Remove and repeat the same process with the zucchini and eggplant. Slice them into 1/2-inch (about 1 cm) rounds, brush with olive oil, sprinkle with salt, and bake.

For the meat sauce: In a pot over high heat, heat the olive oil and add the ground beef. Once it changes color, add the onions and garlic. Cook for a few minutes, then add the tomato paste, stirring and scraping the bottom of the pot until it cooks through. Add the tomatoes, cinnamon stick, bay leaf, salt, and pepper. Simmer for 20-30 minutes until most of the liquid has evaporated. Remove from heat and stir in 2 tablespoons of béchamel sauce.

For the béchamel: In a pot, add all the ingredients except the butter. Whisk constantly over high heat. When it starts to thicken, lower the heat and add the butter. Continue for another 2-3 minutes, then remove from the heat.