Steps
1
Preheat oven to 400°F. Grease a 2-qt baking dish with the cooking spray. Bring a large pot of salted water to a boil. Cook the pasta according to package directions for al dente. Reserve ½ cup cooking liquid before draining in colander.
2
Meanwhile, in a 12-inch skillet, melt the butter on medium. Add the onion and mushrooms, and cook 8–10 min., until softened. Sprinkle the flour over vegetables and cook 1 min. Stir in the broth until thickened. Stir in the cream cheese until dissolved. Stir in the ham, Cheddar cheese, and 4 tbsp Parmesan. Season with salt and pepper.
3
Remove skillet from heat. Stir in the peas and cooked spaghetti, adding pasta water, 1 tbsp at a time, if sauce is too thick. Transfer mixture to prepared baking dish. In a small bowl, combine the bread crumbs, remaining 2 tbsp Parmesan, and oil. Season with salt and pepper. Sprinkle bread crumbs on top of spaghetti mixture.
4
Bake 20–30 min., until filling is bubbly and bread crumbs are golden brown. Top with the parsley before serving, if desired.
