Bring broth to a simmer, remove from heat and cover.
Heat oil in a large skillet over medium heat.
Add onions and saute until tender, about 10 minutes.
Add mushrooms and garlic and continue to cook until mushrooms are tender. Stir in rice and saute until it become translucent.Reduce heat to medium-low.
Add vermouth and cook until the liquid is absorbed.
Add broth, 1 cup at a time, stirring often. Be sure all liquid is absorbed before adding the next cup of broth. Continue until rice is tender and creamy.
Add peas and Parmesan, season to taste with salt and pepper.