In a medium saucepan, heat olive oil over medium heat. Add diced onion and sauté until translucent, about 3-4 minutes. Stir in minced garlic and cook for 1 more minute.

Add sliced mushrooms and stir frequently for about 5-7 minutes until golden brown and tender.

Pour in the Arborio rice, stirring constantly for about 2 minutes to toast the grains.

Add a splash of white wine to deglaze the pan, stirring well. Let simmer for 1-2 minutes.

Begin adding warm vegetable broth, one ladle at a time, stirring constantly until absorbed, about 18-20 minutes.

Once creamy, stir in butter and grated Parmesan cheese off heat.

Transfer to bowls and garnish with optional spinach or herbs. Serve warm.