In a large skillet, heat olive oil over medium heat. Add the diced onion and sauté until translucent, about 3-4 minutes.
Add the sliced mushrooms to the skillet and cook for another 5 minutes until they're soft and golden.
Stir in the minced garlic and dried thyme; cook for an additional minute until fragrant.
Add the orzo pasta to the skillet, stirring to combine with the mushroom mixture.
Pour in the vegetable broth and bring to a simmer. Cook uncovered, stirring occasionally, for about 10 minutes, or until the orzo is tender and the liquid is mostly absorbed.
Stir in the chopped spinach and heavy cream, cook for another 2-3 minutes until the spinach is wilted and the mixture is creamy.
Season with salt and pepper to taste, ensuring flavors are well blended.
Serve warm, garnished with grated parmesan cheese if desired.
Notes
Grated parmesan cheese can be added for extra flavor.