Step 1

Cook noodles in salted water until al dente, or slightly undercooked by 2 minutes. Set aside.

Step 2

Melt the butter in a large deep skillet. Add onions and cook on medium heat until soft, about 5 minutes.

Step 3

Add the flour and a pinch of salt and stir well, cooking an additional 2-3 minutes on medium-low heat

Step 4

Preheat oven to 375°. Lightly spray 9 x 12 casserole with butter flavored cooking spray.

Step 5

Slowly whisk in the chicken broth until well combined, increasing heat to medium and whisking well for 30 seconds, then add the milk and bring to a boil.

Step 6

When boiling, add sherry, mushrooms and petite peas, adjust salt and pepper to taste and simmer on medium, mixing occasionally until it thickens (about 7 to 9 minutes).

Step 7

Add drained tuna, stirring another minute.

Step 8

Remove from heat and add the reduced fat sharp cheddar and mix well until it melts. Add the noodles to the sauce and mix well until evenly coated.

Step 9

Pour into casserole and top with parmesan cheese and breadcrumbs. Spray a little more cooking spray and top and bake for about 25 minutes.

Step 10

Place under the broiler a few minutes to get the crumbs crisp (careful not to burn).