Add the onion, garlic, mushrooms, bay leaf, rosemary and crushed red pepper flakes to the skillet and cook, stirring every now and then until the mushrooms have browned up and the onions start to get tender.
Using a slotted spoon, remove the steeping mushrooms from the chicken stock to a cutting board, chop them coarsely and add them to the skillet along with the red wine. Cook a couple of minutes, then ladle in the fortified chicken stock, being careful to leave some stock behind so you don't pour any grit from the mushrooms that has settled at the bottom of the saucepot into the sauce.
Add the can of plum tomatoes to the skillet and crush them up a little with a potato masher. Add in the browned chicken and let the whole mixture simmer for about 10-15 minutes, until it has thickened up.
Once you have everything in the chicken skillet and it is simmering, place a large pot of salted water over high heat and bring to a boil. Once boiling, add some salt and the pasta, and cook according to the package directions.
Once al dente, drain the pasta and place it back in the pot. Add two ladles of the sauce to the pasta and toss with the Romano cheese. To serve, ladle the pasta into shallow bowls and top with more chicken, mushroom sauce, cheese and parsley.