Heat up a large saute pan on medium to high heat. Add half the oil and sear the Sizzler 3-4 min on each side. Remove from the pan and keep warm.
Add the rest of the olive oil, mushrooms, onion, and garlic to the pan, cooking for 5 min. In a small bowl whisk together the vinegar and sugar and set aside.
Add the beef broth and vinegar mixture to the pan and simmer for 5 min.
Mix the corn starch with 2Tbl of cold water. Remember always add the water to the cornstarch while stirring to prevent lumps. Then add the Herbs to that mixture.
While the sauce is still simmering stir in the cornstarch and simmer for an additional 3-4 min to allow the sauce to thicken.