Sauté onion, green pepper, and celery in 2 tablespoons butter in a large skillet until tender. Stir in tomatoes, 1/2 teaspoon salt, and pepper. Bring to a boil; reduce heat. Cover and simmer 20 minutes or until mixture is thickened, stirring occasionally. Remove from heat, and set aside.
Melt 3 tablespoons butter in a large saucepan over low heat; add flour, stirring until smooth. Cook 1 minute, stirring constantly. Gradually add milk; cook over medium heat, stirring constantly, until thickened and bubbly. Add Worcestershire sauce and remaining salt; stir well. Stir in vegetables and eggs. Spoon into a lightly greased 2- quart casserole.
Combine breadcrumbs and 2 tablespoons melted butter; sprinkle over casserole. Bake at 350° for 20 minutes or until hot and bubbly. Serve immediately.