Place the eggplant slices on a baking sheet, sprinkle with salt, and let them sit for about 30 minutes to release excess moisture.
Preheat the oven to 400°F (200°C).
Pat the eggplant slices dry and brush both sides with olive oil. Bake in the preheated oven for 15-20 minutes or until tender. Set aside.
In a skillet, heat olive oil over medium heat. Add minced garlic and Italian Mix frozen vegetables. Cook for 5-7 minutes or until the vegetables are tender.
Add the diced tomatoes, dried oregano, salt, and pepper. Simmer for an additional 5 minutes. Set aside.
In a saucepan, melt the butter over medium heat. Add the flour and whisk constantly for 1-2 minutes to form a roux.Gradually add the milk, whisking continuously to avoid lumps. Cook until the sauce thickens. Season the bechamel sauce with salt and pepper. Remove from heat and let it cool slightly. Stir in the grated Parmesan cheese and beaten eggs. Mix until smooth.
In a baking dish, layer half of the eggplant slices.Spoon vegetable filling over the eggplant layer. Add the remaining eggplant slices on top.
Pour the bechamel sauce over the top, ensuring it covers the entire surface.
Bake the moussaka in the preheated oven for 40-45 minutes or until the top is golden brown and the filling is set.
Let the moussaka rest for a few minutes before slicing.