This Tuna Noodle Casserole is a classic, comforting dish just like Mom used to make!
Preheat oven to 375 degrees. Spray a 4-qt. baking dish or 9x13 pan with nonstick cooking spray. Set aside.
Cook pasta, al dente, according to package directions. Drain. Return noodles to pot.
In a large saucepan, over medium heat, melt butter. Add the mushrooms, green pepper and onions, cook until softened, about 8-10 minutes, stirring often. Stir in the flour and cook for an additional 1-2 minutes. Slowly add the vegetable broth, stirring until well combined. Add the milk and salt and pepper and continue to cook until the mixture bubbles and is slightly thickened. Add the sauce to the noodles along with the tuna and stir until well combined. Add the mixture to the prepared dish.
In a small bowl, toss the shredded cheddar, Parmesan cheese and panko crumbs. Sprinkle over the noodles. Bake uncovered for 30 minutes or until bubbling and heated through. Remove from oven and let stand for 5 minutes before serving.