Sauté the Vegetables
Heat olive oil and butter in a large skillet over medium heat. Add the onion and garlic, cooking until fragrant and translucent. Stir in the sliced mushrooms and cook until softened and slightly browned, about 5 minutes.
Toast the Orzo
Add the orzo to the skillet, stirring to coat it in the oil and butter. Toast the orzo for 1-2 minutes until lightly golden, which enhances its flavor.
Cook the Orzo
Pour in the broth and water. Bring the mixture to a simmer, then reduce the heat to low. Cover the skillet and cook for 8-10 minutes, stirring occasionally, until the orzo is tender and most of the liquid is absorbed.
Add Cream and Spinach
Stir in the heavy cream and chopped spinach. Cook for another 2-3 minutes, allowing the spinach to wilt and the sauce to thicken slightly.
Incorporate Parmesan Cheese
Mix in the Parmesan cheese, stirring until melted and combined. Season the dish with salt and pepper to taste.
Serve and Garnish
Remove from heat and garnish with additional Parmesan cheese or chopped parsley, if desired. Serve warm