Heat the olive oil in a non-stick pan over medium heat. Season the steak well with salt and pepper.
Sauté the mushrooms, shallots, and garlic for about 3 minutes until the mushrooms start to soften. Add in the sirloin and sauté until it starts to brown.
Add the flour to the pan. Cook for 1 minute, stirring constantly.
Stir in the beef broth, thyme, and rosemary. Cover with a lid and bring to a low simmer for about 15-20 minutes. Taste and adjust the seasoning with salt and pepper as needed. Remove the thyme and rosemary sprigs.