One-Pot Creamy Chicken and Mushroom Pasta with Peas

• 2 tspextra-virgin olive oil
• 1small onion — chopped
• 8 ozwhite button mushrooms — sliced
• 2garlic — minced
• ½ tspkosher salt
• ¼ tspblack pepper
• 454 gwhole wheat penne pasta — 1 box, or regular penne pasta
• 3 cupslow-sodium chicken broth
• 4 ozplain cream cheese — one-third reduced fat
• 2 cupsshredded mozzarella cheese
• 10 ozfrozen peas — thawed, 1 bag
• 2 cupscooked shredded chicken

For serving:

• ¼ cupfresh parsley — chopped, optional
• —Shredded Parmesan cheese — optional