Start by warming the chicken broth. Either in a large bowl in the microwave or in a medium saucepan over medium heat bring to a simmer.
In a large pot heat the olive oil. Add the onion and cook until tender. Add 1 tbsp butter, garlic, mushrooms and thyme. Cook until the mushrooms have softened and are tender. Season with salt and pepper. Remove and set aside on a plate.
Melt the remaining 1 tbsp butter and add the arborio rice. Stirring on medium heat, cook the grains until the are lightly brown and start to toast about 2 minutes. Add the wine and cook until the wine has absorbed.
Add one cup of broth at a time to the rice and stir frequently until the rice absorbs the liquid. Continue to add one cup of broth and allow the rice to absorb after each addition. Stir often and cook until the risotto is al dente and not mushy. You may not need all of the broth.
Add the mushrooms, parmesan, and peas back to the rice and stir. Garnish with fresh parsley. Serve while warm.