Preheat the oven to 375°F (190°C).
Make the moussaka: Place eggplant slices on a baking sheet. Sprinkle with salt and let sit for 15 minutes. Rinse and pat dry.
Heat olive oil in a skillet over medium heat. Add lamb, onion, and garlic. Cook until lamb is browned.
Stir in diced tomatoes, oregano, cinnamon, salt, and pepper. Simmer for 10 minutes.
Make the béchamel sauce: In a saucepan over medium heat, melt butter for the béchamel sauce. Whisk in flour.
Gradually whisk in milk until smooth and thickened. Season with salt and pepper.
Grease a baking dish with olive oil. Layer half the eggplant, then half the meat mixture. Repeat layers.
Top with béchamel sauce, breadcrumbs, and Parmesan.
Bake for 40 minutes, until golden and bubbly. Let cool slightly before serving. Garnish with parsley if desired.
Heat pita bread in a skillet until soft and warm. Cut into wedges.
Make the tzatziki sauce: In a blender, combine cucumber, Greek yogurt, garlic, dill, olive oil, salt, and pepper. Blend until smooth and refrigerate.
Stir together almond milk, cinnamon, and honey until blended. Chill if desired.
Serve moussaka with pita, tzatziki, and almond milk with cinnamon and honey.