Cook Pasta : In a large saucepan or pasta pot, cook the penne pasta according to the box directions. Cook to al dente or softer depending on your preference.* It's important to add salt to the boiling water along with the pasta. I use about 1-2 teaspoons of kosher salt. 1 box (16 oz) penne pasta
Reserve 1/2 cup of the pasta water before draining the pasta, do not rinse it, and leave it inside the pot with the lid on and set it aside for later.
Melt the butter in a large skillet pan, over medium heat, and add the onion and garlic. Cook until the onion is translucent and the garlic is fragrant, about 3-5 minutes.
4 tablespoons butter, 1/2 cup finely chopped onion, 2 teaspoons minced garlic
Stir in the sliced mushrooms and cook for 5 minutes, while stirring frequently, until the mushrooms have released their juices and softened.
1 package (8 oz) sliced mushrooms
Pour in the chicken broth and use a rubber spatula, or wooden mixing spoon, to stir and scrape the bottom of the skillet to remove all the stuck-on bits.
1 cup chicken broth
Add in the cream of mushroom soup, heavy cream, Italian seasoning, and flour. Mix thoroughly until combined.
1 can (10.5 oz) cream of mushroom soup, 1 cup heavy cream, 1 teaspoon Italian seasoning, 1 tablespoon all-purpose flour
Turn the heat up to medium-high and add in the cooked chicken. Bring to a simmer (gentle boil around the edges) and simmer, while stirring occasioanly, for 10 minutes until thickened and combined.
2 cups shredded or chunked cooked chicken
If needed, add some of the reserved pasta water to reach your preferred consistency.
Stir the cooked pasta into the creamy mushroom sauce until thoroughly combined. Garnish with parmesan cheese and chopped parsley if wanted. Serve warm!
parmesan cheese & chopped parsley