In a large skillet, heat the olive oil over medium heat. Add the onion and sauté until translucent, about 5 minutes. Add the garlic and cook for another minute until fragrant.

Cook the Mushrooms

Add the chopped mushrooms to the skillet and sauté until they are browned and tender, about 5-7 minutes.

Toast the Rice

Add the Arborio rice to the skillet and stir well to coat the rice with the oil and juices. Cook for about 2 minutes until the rice is slightly translucent.

Add Broth Gradually

Begin adding the warm vegetable broth, one ladle at a time, stirring frequently. Allow the rice to absorb most of the liquid before adding more broth. Continue this process for about 18-20 minutes, or until the rice is creamy and al dente.

Add Spinach and Sage

When the rice is nearly done, stir in the fresh spinach and chopped sage, cooking until the spinach wilts.

Finish with Parmesan

Remove from heat and stir in the grated Parmesan cheese. Season with salt and black pepper to taste.

Serve

Serve hot, garnished with additional Parmesan and sage if desired.