Set the steaks out 30 minutes prior to cooking to allow them to come to room temperature. Season them with the garlic, salt, and pepper.
2 6 oz sirloin steaks, 1 tsp garlic powder, salt & pepper
Add the oil and butter to a large cast iron skillet set over medium high heat. Once melted add the steaks and sear for 5 minutes, undisturbed. Flip them over and continue cooking for 5 more minutes, again without touching them.
1 tbsp extra virgin olive oil, 1 tbsp butter
Transfer the steaks to a waiting plate, cover with foil, and set aside.
Reduce the heat to medium and add the mushrooms and shallots to the skillet. Cook for 5 minutes, stirring occasionally. Stir in the wine, then reduce the heat to medium low and let simmer for 2 minutes.
8 oz crimini mushrooms (stems removed), 2 shallots, 1/2 cup marsala wine
Add the broth and mustard, stirring until evenly incorporated. Bring the mixture to a simmer and cook until the sauce reduces by half, about 5 minutes.
3/4 cup beef stock, 1 tsp Dijon mustard
Plate the steaks, spoon the sauce overtop, serve immediately, and enjoy!