Bring a large pot of water to a boil. Cook noodles until just tender, 6 to 8 minutes or according to package directions. Drain and rinse.

Position rack in upper third of oven and preheat broiler.

Meanwhile, heat oil in a large ovenproof skillet over medium-high heat. Add onion, mushrooms and salt and cook, stirring often, until the onion is softened but not browned, about 5 minutes. Add wine and cook until evaporated, 4 to 5 minutes. Sprinkle flour over the vegetables; stir to coat. Add milk and pepper and bring to a simmer, stirring constantly. Stir in tuna, peas and 1/2 cup Parmesan until evenly incorporated. Then, stir in the noodles (the pan will be very full). Remove from the heat.

Sprinkle the casserole with breadcrumbs and the remaining 1/2 cup Parmesan. Broil until bubbly and lightly browned on top, 3 to 4 minutes.

Tips: Chunk light tuna, which comes from the smaller skipjack or yellowfin, has less mercury than canned white albacore tuna. FDA/EPA advice recommends no more than 6 ounces of albacore a week; up to 12 ounces canned light is considered safe.

To make fresh breadcrumbs, trim crusts from whole-wheat bread. Tear bread into pieces and process in a food processor until coarse crumbs form. One slice of bread makes about 1/2 cup fresh crumbs. For dry breadcrumbs, spread the fresh crumbs on a baking sheet and bake at 250 degrees F until crispy, about 15 minutes. One slice of fresh bread makes about 1/3 cup dry crumbs. Or use prepared coarse dry breadcrumbs. We like Ian's brand labeled "Panko breadcrumbs." Find them in the natural-foods section of large supermarkets.

MAKE AHEAD TIP: Prepare through Step 3, spoon into an 8-inch-square glass baking dish, cover with foil and refrigerate for up to 1 day. Sprinkle with breadcrumbs and cheese (Step 4) and bake, covered, at 350 degrees F for 50 minutes. Uncover and cook until browned and bubbly, about 15 minutes more.