For the lamb Bolognese: In a large, heavy-bottom pot or Dutch oven over medium-high heat, heat oil. Add lamb, onion and salt; break up the meat with a metal spatula. Cook 10 to 12 minutes, stirring often until onions are tender and meat is browned; drain any fat. Splash with wine; cook until evaporated, about 2 minutes. Add garlic, cinnamon, cumin, oregano and pepper; sauté 2 minutes until garlic is fragrant. Stir in crushed tomatoes and tomato paste; simmer on low heat, covered, for 20 minutes. Taste; add more salt if desired. 

For the Béchamel: In a medium pot over medium heat, heat the oil. Whisk in flour into a smooth paste; cook for 60 seconds. Whisk in 1 cup milk until smooth and thickened. Immediately add remaining 1-1/2 cups milk; whisk until smooth and thickened again. Add parmesan, salt, nutmeg and pepper; stir until cheese melts and sauce is smooth. Set aside; cool for 10 minutes. 

Cook the pasta according to package directions; drain. 

Once Béchamel has cooled 10 minutes (warm is ok, just not hot), stir in yogurt and beaten eggs.

Add cooked pasta to the Bolognese; mix. Pour into an extra large greased baking dish (9 X 13) or 12-inch ovenproof skillet. Top with Béchamel sauce, covering it evenly. Sprinkle with 1/2 cup more parmesan and scatter with fresh thyme leaves. Bake at 400°F 30 to 40 minutes or until golden and bubbly.