Add to your large, deep skillet 1 tablespoon olive oil. Sauté the mushrooms in two batches (each with 1 tbs olive oil), about 5 minutes each batch. Season with salt and pepper to taste. Transfer browned mushrooms to a plate and set aside.
Add 1 tbs of butter to the pan and your onion. Sauté for 2-3 minutes then stir in the garlic for 30 seconds. Next stir in the orzo for 1 minute. Add the mushrooms back in the pan along with the broth, heavy cream, milk, herb blend seasoning and salt and pepper to taste. Bring to a boil and then lower heat to a simmer. Stir constantly until orzo is cooked through al dente.
Remove from heat and add in the remaining 1 tbs of butter, grated parmesan - stir to combine. Lastly fold in the spinach and parsley. Serve with extra parmesan or parsley.