Cook noodles al dente, according to package directions.
In a large skillet, melt the butter over medium-high heat. Stir in the onion, garlic, and peas and carrots; season with the salt and pepper. Cook for about 3 minutes until onions are soft and translucent. Stir in the flour until combined.
Pour in the chicken broth and heavy cream; bring to a boil. Reduce to a simmer. Stir occasionally until thickened, about 5 minutes.
Drain the pasta and add to the skillet, along with the chicken. Taste and season with a touch more salt and pepper, if necessary.
Serve hot and enjoy!
