Preheat the oven to 375°F (190°C).
Prepare the pasta layer: Cook ziti according to the directions on the package.
Prep onion for the main dish per instruction above. If cheese is not shredded, shred per instruction above.
Prepare the meat layer: Melt the butter in a large skillet on medium heat. Add the onions and saute until softened and golden brown. Crumble the beef into the skillet and cook with the onions until the beef is browned. Stir in the cinnamon, and salt and pepper to taste. Stir in the water and tomato paste, and simmer for 5 minutes. While simmering, make the bechamel sauce.
Prepare the bechamel sauce: Melt the butter in a medium saucepan. Whisk in the flour and then gradually whisk in the milk. Cook, whisking constantly until the sauce is smooth and thickened. Season with salt to taste, remove from heat and let cool.
Finish pasta layer: When the ziti is cooked, drain well and rinse with cool water. When pasta has cooled down, stir in the beaten eggs.
Finish bechamel sauce: When the sauce has cooled down to lukewarm, whisk in the egg. Set aside.
Assemble: Spray a deep 8x8 baking dish (or appropriately sized baking dish according to the portions being made) with nonstick spray.
Scoop half of the pasta into the bottom of your prepared dish. Sprinkle generously with cheese. Spoon on the meat mixture to create an even layer; sprinkle with another layer of cheese. Scoop the remaining pasta on top of the meat and sprinkle with more cheese! Top with the bechamel sauce and sprinkle with the remaining cheese.
Bake for 35 to 45 minutes, or until the sauce is bubbly and golden on top. While baking, prep salad and vinaigrette.
Prep cucumber and tomato per instruction above. Place the spring mix in a bowl with cucumber and tomato on top. Use a vegetable peeler to shave the carrot onto the top of the salad.
Make vinaigrette: Whisk together ingredients for the vinaigrette with salt and pepper to taste.
Finish pastito: Once the pastitois baked, let sit at room temperature for 15 to 20 minutes before serving.
Finish the salad: Dress with vinaigrette just before serving.
Serve the pastitsio with side salad and sparkling water.