Rinse and slice your broccoli into florets and dice the stems too.
To a pot, add the oil and heat to medium high. Saute mushrooms until lightly golden brown on each side. Stir in the garlic for 30 seconds. Next, add in the broccoli, broth, water, salt and pepper to taste. Bring to a boil and then reduce heat to a simmer. Cover your pot and cook for 20 minutes.
Using a potato masher to gently smash the broccoli - about 6 times. Leave large and small pieces in the soup for texture. Add in the orzo and cook uncovered, STIRRING CONSTANTLY, for 15 minutes or until pasta is cooked. Stay on top of the pot, the pasta will stick if left unattended. Taste and adjust seasonings if needed.
Remove the pot from the burner and add in chicken and parmesan and mix it in. Serve in your bowls, drizzle with a little olive oil, squeeze on some lemon juice and top with chili pepper flakes to taste.