Cook the pasta according to the package directions.
In a large skillet, heat the olive oil over medium-high heat. Add the chicken, and cook for 5-6 minutes, until chicken is cooked through. Remove from pan, and keep warm.
Melt the butter in a Dutch oven or stockpot over medium-high heat, and cook the onions and garlic for about 5 minutes until soft and translucent.
Add the flour, and stir to combine.
Next, add the broth, Alfredo sauce, milk, and heavy cream (if using) and stir to combine. Increase the heat and bring it to a boil, stirring regularly, until the sauce thickens slightly.
Add the grilled chicken, tomatoes, and mushrooms to the pot. Stir to combine, and return to a boil. Reduce the heat to medium-low and simmer with a lid on for 15 minutes, stirring occasionally.
Finally, add the parsley and cooked bow-tie pasta. Stir to combine and simmer for another 2 minutes. Add salt and pepper to taste, and serve hot.
