Place a large heavy-bottomed pan over med/high heat and melt in 2 Tbsp butter and 1 Tbsp oil. Add sliced mushrooms and cook 6 min or until softened and most of the liquid has evaporated. Add diced onion and cook 3 min, stirring often.

Add minced garlic, 1 Tbsp thyme, ¼ tsp salt and ⅛ tsp black pepper. Cook, stirring constantly, 2 min or until garlic is fragrant. Transfer mushrooms to a large plate. Wipe pan clean with a wet paper towel.

Season steaks all over with 1 tsp salt and ¼ tsp black pepper. Place the same pan over medium/high heat and add 2 Tbsp butter and 1 Tbsp oil. When the butter is hot and finished foaming, add seasoned steaks and sear 3-5 min per side for medium-rare (5-6 min for medium doneness*), turning once. When steaks reach desired doneness, transfer them to the plate with mushrooms.

In the same pan over med/high heat, add ½ cup red wine and boil down until reduced by half (3 min), scraping the bottom to deglaze. Add 1 ½ cups beef broth and boil until ⅔ cup of liquid remains in the pan (5-7 min). Stir in ½ cup cream and boil 2 min or until slightly thickened. Season sauce to taste with salt and pepper if desired.

Add steaks and mushrooms back to pan, spooning some of the sauce over steaks. Once steaks are just heated through, remove from heat and serve garnished with fresh sprigs of thyme if desired.