Boil one 16 oz box of penne pasta in salted water.
While the pasta cooks chop 1/2 a large yellow onion.
In a LARGE sauce pan warm 2 tablespoons olive oil.
Sauté the onion in that oil. salt and pepper the onion. Cook until tender.
Add 4 tablespoons flour to the onion and stir so all the onion is well coated.
Slowly add 3 and a half cups of chicken stock to the onions. Bring it to a boil then summer so it can thicken. This can take up to ten minutes. Also add 1/2 a cup of whole milk. Salt and pepper to taste.
Add 2 cans chunk light tuna to the sauce. Then add a cup and a half of peas to the sauce. Mix with the cooked pasta and taste. Add salt or pepper as needed.
Place pasta mixture in 9x13 pan. Cover with sprinkling of Parmesan cheese powder. Then with about a cup or so of Panko bread crumbs.
Spray the top with an olive oil mist. Place in 425 degree oven for 17-18 minutes until golden brown on top.