In a large skillet add half the olive oil over medium-high heat and add the sliced mushrooms cooking them for 1-2 minutes on each side before removing to a plate.
Lower the heat to medium, add the rest of the olive oil along with the diced mushrooms, carrots and onions and cook until well caramelized, about 8-10 minutes before removing and placing with the sliced mushrooms.
Raise the heat to medium-high again and add the beef to the pan letting it get a good sear before breaking it apart (about 2-3 minutes) and continue cooking until the beef is fully cooked (4-5 more minutes).
Add the salt, pepper, thyme and vegetables back into the pan and stir together along with the garlic, for about 1 minute.
In a measuring cup whisk together the Worcestershire sauce, beef broth and cornstarch before adding it to the pan and letting the sauce thicken for 2-3 minutes.