• Preheat your oven to 350°F. Prepare a 8x8-inch baking dish with a light coating of butter or nonstick cooking spray.

Prepare The Pasta:

• Boil the pasta in salted water until just under al dente, about 1–2 minutes less than package directions. Drain and set aside.
  

Make The Meat Sauce:

• In a large skillet, heat the olive oil over medium-high heat.
• Add the beef. Cook, breaking up the meat with a wooden spoon, until browned, about 4–5 minutes.
• Add minced garlic and cook for 1 minute until fragrant.
• Stir in the crushed tomatoes, tomato paste, bay leaf, and cinnamon. Season with salt and pepper.
  
• Simmer on low heat for 30 minutes, stirring occasionally, until thick. Remove and discard the bay leaf after simmering.

Make The White Sauce:

• In a large saucepan, melt the butter over medium heat.
• Whisk in the flour; stir for 1 minute until foamy.
• Gradually whisk in the milk, stirring constantly to avoid lumps.
• Simmer gently for 5 minutes, until thick enough to coat a spoon.
• Remove from heat. Stir in the grated Parmesan and season to taste with salt and black pepper. Whisk in a pinch of nutmeg if desired.
  

Assemble And Bake The Dish:

• Layer the cooked pasta in the prepared baking dish, arranging noodles in the same direction for neat slices.
• Spread the meat sauce evenly over the pasta.
  
• Pour the white sauce over the meat sauce, gently evening it out with a spatula.
• Sprinkle crumbled feta cheese evenly over the top. Optionally, add a bit more grated Parmesan.
• Bake in preheated oven for 30 minutes, or until the top is bubbly and golden.
• Remove from oven and let the dish rest for 10 minutes before slicing, so the layers set and slices hold their shape.
• Garnish with fresh thyme leaves, if desired, and serve warm.