Heat olive oil in a pan over medium heat. Add the mushrooms and saute about 4 minutes.Stir in the garlic and thyme and saute an additional minute. Set aside.In a large pan, heat the butter over medium high heat.Add the orzo and brown.Pour in the chicken broth and bring to a boil.Reduce heat and stir until reduced.Stir in the mushroom mixture and Parmesan cheese.