Preheat oven to 350 degrees F.

Sprinkle eggplant with salt and place between paper towels for 15 minutes to draw out moisture.

On roasting pan, arrange eggplant and spray evenly with olive oil; roast for 20 minutes or until cooked through.

In large pan over medium-high heat, add beef/lamb, cinnamon, oregano, ginger, allspice, cayenne, salt and pepper and brown for 5 minutes. Drain and set aside.

To pan, add onion and bell pepper and sauté 5 minutes. Add serrano pepper and garlic and cook until fragrant, about 5 minutes, then stir in tomato paste and cook for 1 minute.

Stir meat into pepper and onion mixture, add red wine and cook for 5 minutes, until reduced and wine is almost evaporated.

Add tomato puree, bring to boil then reduce to simmer. Add sugar, bouillon and water, stir to combine. Let simmer.

In 3-quart baking dish, layer potato first, then zucchini, followed by half of eggplant. Add beef mixture, then top with remaining eggplant.

Preheat oven to 400 degrees F.

To make béchamel sauce, in saucepan over medium heat, melt butter then stir in flour until well combined.

Slowly whisk in milk and stir until thickened, 5-10 minutes. Add salt, bay leaf, nutmeg and pepper. Remove from heat and stir in cheese until melted. Whisk in egg yolks. Once well combined, pour over eggplant in baking dish.

Bake for 45 minutes. Let rest 20 minutes before serving.