01 -  Heat olive oil and butter in a large heavy-bottomed skillet over medium heat. Add chopped onion and sauté until translucent, about 3 minutes. 
 02 -  Stir in mushrooms and cook until softened and lightly browned, approximately 7 minutes. Add minced garlic and cook for 1 minute, stirring frequently. 
 03 -  Add Arborio rice to the pan and stir continuously until edges turn translucent, roughly 2 minutes. 
 04 -  Pour in white wine and cook, stirring, until almost fully absorbed. 
 05 -  Ladle in 1 cup of warmed chicken broth, stirring regularly until the liquid is absorbed. Continue adding the remaining broth, 1 cup at a time, allowing each addition to be absorbed before pouring more. This process should take about 25 minutes. 
 06 -  Once rice is creamy and tender yet al dente, fold in Parmesan cheese and fresh thyme leaves. Season generously with salt and pepper. 
 07 -  Transfer risotto to serving plates and garnish with additional thyme or Parmesan, if desired.