Heat 1 tablespoon olive oil and 1 tablespoon butter in a large sauce pot (3-4qt), add shallots and garlic, sauté until translucent.
Add mushrooms and sauté for approx. 4-5 minutes until tender; remove and set aside.
Add remaining olive oil and arborio rice and sauté over medium heat to toast the rice approximately 3 minutes.
Add one cup of the simmering chicken stock, stirring constantly, and simmer until the stock is absorbed.
Continue adding stock as it is absorbed, 1/2 cup at a time, until all the liquid is absorbed.
Just before the rice is done, add the fresh thyme and reserved mushrooms. Stir to combine.
Add salt and pepper to taste, and serve.