Peel the uncooked squash, cut in half and remove seeds. Dice into 1/2” cubes (approx. 6 c). Season with salt and pepper and steam or sauté until tender (approx. 15 min); set aside. In a large sauce pan, add olive oil and onion and sauté 3 min. Add beef and lamb and cook 6-8 min; drain all excess fat. Add wine, parsley, tomatoes and seasonings; simmer 10 min. Add breadcrumbs, adjust seasoning; set aside. Cook pasta in boiling, salted water until al dente. Drain and toss with butter, eggs and 1 c Parmesan; set aside. Prepare Béchamel sauce, below.
Preheat oven to 350 degrees. Spray 9”x13” dish with cooking spray. Place half of the pasta on the bottom in an even layer pressing lightly. Spoon meat mixture over pasta, spread evenly. Top with squash, repeat with remaining pasta, pressing down lightly. Finish with Béchamel, and sprinkle with 1/2 c Parmesan. Bake 45 min, until crust is light golden brown. Let rest 20 min before serving.
In a sauce pan, melt butter, slowly whisk in flour and stir constantly approx. 5 min. Add milk, whisking constantly. Stir until sauce has thickened. Remove from heat and stir in eggs, nutmeg, salt and pepper.
* Choose lean ground beef, 7% fat or less, for best results.