Begin by taking your filet mignon out of the refrigerator. Pat the steaks dry with paper towels and season generously with kosher salt and black pepper. Allow them to rest at room temperature for 30 to 60 minutes.

While the steaks are resting, prepare your ingredients. Slice the baby bella mushrooms into even pieces and mince the garlic. In a small bowl, mix all-purpose flour, garlic powder, and onion powder.

Heat a large skillet over medium-high heat and add the olive oil and unsalted butter. Once the butter foams and turns slightly golden, coat each steak lightly with the flour mixture. Sear the steaks for about 2-3 minutes on each side.

Once seared, remove the steaks from the skillet and cover them loosely with foil to rest while you prepare the sauce.

In the same skillet, add the sliced mushrooms and cook over medium heat, stirring occasionally, until soft and golden, about 5 minutes. Add the minced garlic and fresh thyme, sautéing for another minute.

Pour in the marsala wine and gently scrape up any browned bits from the bottom of the skillet. Allow it to simmer for about 3-4 minutes. Then, add the beef stock and let it simmer for an additional 3-4 minutes.

Reduce the heat to low and stir in the heavy cream. Return the rested steaks to the skillet, spooning the sauce over them, and simmer together for 3-5 minutes.

Carefully plate the steak whole or sliced, drenching it in the creamy marsala sauce dotted with mushrooms.