Melt Becel® Buttery Taste margarine in large saucepan over low heat and stir in flour with wire whisk until blended. Cook 2 minutes, stirring frequently. Slowly add milk, stirring constantly with wire whisk. Stir in 1/2 cup (125 mL) cheese. Simmer, stirring constantly, over medium-low heat, until sauce starts to thicken, about 10 minutes.
Stir in Hellmann's® Real Mayonnaise and black pepper until blended. Stir in tuna, peas, corn and parsley, then pasta. Turn into 2-quart (2 L) baking dish, then sprinkle with bread crumbs and remaining cheese.
Bake 20 minutes or until golden and cheese is melted.