In a large saucepan, heat olive oil or butter over medium heat.
- Add onion and cook until soft and translucent, about 5 minutes.
- Stir in garlic and mushrooms. Sauté for 6–8 minutes, until mushrooms are browned and tender.
- Add Arborio rice and stir to coat, cooking for 1–2 minutes to lightly toast the grains.
- If using wine, pour it in and stir until mostly evaporated.
- Add warm vegetable broth one ladle at a time, stirring frequently and letting each addition absorb before adding the next, for 18–20 minutes.
- Stir in peas during the last 5 minutes of cooking.
- When rice is tender and creamy, stir in Parmesan cheese or nutritional yeast. Season with salt and pepper.
- Remove from heat and rest for 2 minutes.
- Garnish with fresh herbs and serve hot.