In a food processor, combine the dried porcini mushrooms and pulse until finely ground. In a bowl, mix the ground porcini with chopped thyme, salt, and pepper. Set aside.

In a separate bowl, combine the softened butter, black truffle oil, chives, and parsley. Mix well until all ingredients are incorporated. Transfer the compound butter onto a sheet of plastic wrap, shape it into a log, and refrigerate until firm, about 30 minutes.

Preheat your oven to 400°F (200°C). Heat olive oil in a large oven-safe skillet over medium-high heat. Season the filet mignon steaks with salt and pepper on both sides. Once the oil is hot, add the steaks to the skillet and sear for 3-4 minutes on each side until a golden crust forms.

Once seared, remove the skillet from heat. Press the porcini mushroom mixture firmly onto the top of each steak to form an even crust.

Transfer the skillet to the preheated oven and bake for 6-10 minutes for medium-rare, or until desired doneness is reached. Use a meat thermometer to check the internal temperature (130°F for medium-rare).

Once cooked to your liking, remove the skillet from the oven. Let the steaks rest for 5 minutes before serving. Slice the chilled truffle butter into medallions and place atop each filet mignon just before serving.