Cook pasta (8 ounces) according to package directions until just al dente. Drain and set aside.
In a saucepan, melt butter (2 tablespoons) then saute mushrooms (1 1/2 cups) and onion (1/2 cup) until both are nice and soft.
In a large bowl mix soup (2 cans), sour cream (1 cup), Worcestershire sauce (1 teaspoon), and black pepper (1/2 teaspoon) until blended. And cooked mushrooms, onion, chicken (1 fully cooked), and spaghetti and fold until everything is evenly coated with sauce.
Pour the spaghetti into a 9x13 dish and top with cheese (1 cup). Bake in a preheated oven for about 30 minutes or until the casserole is heated through.
Notes
Sauté The Vegetables: When starting this cheesy chicken noodle casserole, it’s important to sauté your veggies first. Don’t skip this step. It brings out their balanced mellow flavors and produces a more cohesive flavor profile in the finished product. Trust me on this one. Here’s an article from Serious Eats on what sautéing does to them.
Pasta – One important thing, though. Be sure you only cook your pasta just until al dente so it doesn’t turn into a mushy mess in the oven.
You’ll also want to use good quality Italian pasta that can withstand the high oven temp without disintegrating. I like Barilla spaghetti.
All about that crunch. Want to really jazz up this casserole? Sprinkle some crushed crackers over the top after baking, when the cheese is still bubbly and gooey. The extra texture is drool-worthy, while the added flavor of the cracker packs a fun punch. I like to use Ritz