Preheat the grill or oven to 350°F.
In a mixing bowl, combine the cream cheese, Worcestershire sauce, green onions, garlic, and crawfish. Stir until well blended.
In a medium saucepan, melt the butter over medium heat.
Stir in the flour and cook for about 2 minutes, or until the flour turns a light caramel color.
Slowly whisk in the milk, then add the Parmesan cheese.
Continue stirring until the sauce slightly thickens.
Grease a 9x9 casserole dish.
Add the cooked noodles, followed by the crawfish mixture, then pour the sauce evenly over the top.
In a small bowl, mix the topping ingredients together and sprinkle evenly over the casserole.
Cover with foil and bake for 20 minutes.
Remove the foil and bake for an additional 15 minutes, or until the top is bubbly and golden brown.