In a medium pot, bring salted water to a boil. Add the orzo and cook according to package instructions until al dente. Drain and set aside.
In a large skillet, heat olive oil over medium heat. Add the diced onion and sauté for about 3-4 minutes until softened. Stir in the minced garlic and cook for an additional 1 minute until fragrant.
Add the sliced mushrooms to the skillet. Cook for about 5-6 minutes, stirring occasionally, until the mushrooms are golden brown and any moisture has evaporated.
Stir in the fresh spinach and cook until wilted, about 2-3 minutes.
Pour in the vegetable broth and bring to a simmer. Reduce heat to low, then mix in the heavy cream or coconut cream, dried thyme, lemon zest, salt, and pepper. Let it simmer gently for 3-4 minutes, allowing the sauce to thicken slightly.
Add the cooked orzo to the skillet and stir until the pasta is fully coated with the creamy sauce. If using, stir in the grated Parmesan cheese until melted and well combined.
Taste and adjust seasoning with more salt, pepper, or lemon zest as desired.
Divide the creamy mushroom spinach orzo among plates or bowls. Garnish with fresh parsley if using and enjoy!
Notes
For a lighter option, use coconut cream instead of heavy cream.