Heat the vegetable broth in a saucepan and keep it warm on low heat.
In a large, deep skillet or saucepan, heat the olive oil over medium heat.
Add the chopped onion and garlic to the skillet and sauté for a few minutes until they become translucent.
Add the sliced mushrooms to the skillet and cook until they start to brown and release their moisture.
Stir in the Arborio rice and cook for a couple of minutes until the rice is lightly toasted.
If using, pour in the white wine and stir until it's mostly absorbed by the rice.
Begin adding the warm vegetable broth, one ladle at a time, stirring frequently. Allow each addition of broth to be absorbed before adding more. This gradual process should take about 18-20 minutes, and it's essential for achieving the creamy texture of risotto.
When the rice is creamy and cooked to your desired level of tenderness, stir in the vegan butter (if using), nutritional yeast, salt, and pepper.
Remove the skillet from the heat, garnish with fresh chopped parsley, and serve hot.
Optionally, sprinkle vegan Parmesan cheese on top before serving.Enjoy your delicious vegan mushroom risotto!