In a medium saucepan, bring the vegetable broth to a simmer. Add the orzo and cook according to package instructions until al dente, about 8-10 minutes. Drain and set aside.
In a large skillet, heat the olive oil over medium heat. Add the chopped onion and sauté for 3-4 minutes until it becomes translucent.
Stir in the minced garlic and sliced mushrooms, cooking until the mushrooms are browned and tender, about 5-7 minutes.
Add the chopped spinach to the skillet and cook until wilted, about 2-3 minutes.
Pour in the heavy cream, stirring until the mixture is well combined. Allow it to simmer for a few minutes until slightly thickened.
Stir in the cooked orzo, followed by the Parmesan cheese. Mix well until the cheese is melted and creamy throughout the dish.
Season with salt, pepper, dried thyme, and nutmeg (if using) to enhance the flavors. Adjust to taste as needed.
Remove from heat and garnish with fresh parsley before serving.
Notes
For a dairy-free option, use coconut cream and nutritional yeast.