Heat oven to 350 degrees F. Grease 13 x 9 x 2-inch baking dish. Stir cream cheese, scallions, milk and Old Bay seasoning in large bowl until smooth. Stir in peppers, reserving 1/2 cup, and broccoli, reserving 1 cup. Add crabmeat, 1 egg, salt and black pepper. Whisk remaining egg into alfredo sauce.
Spread 1/3 cup alfredo sauce into prepared baking dish. Top with 3 noodles and 1/3 crab mixture. Repeat, layering twice with noodles, crabmeat, noodles, crabmeat. Top with 3 noodles; sprinkle with reserved red pepper and broccoli. Pour on remaining alfredo sauce. Sprinkle with Parmesan.
Bake, covered, in 350 degree F oven 30 minutes. Uncover; bake 20 to 25 minutes, until browned and bubbly. Let stand 10 minutes. Makes 12 servings.