In a small bowl, combine the softened butter, dried porcini mushrooms, parsley, thyme, rosemary, and cracked black peppercorns. Mix well until all ingredients are evenly incorporated. Transfer the mixture onto a piece of plastic wrap, shape it into a log, and refrigerate until firm.

In a medium skillet, heat 1 tablespoon of olive oil over medium heat. Add the chopped shallots and a pinch of salt. Cook, stirring occasionally, until the shallots are soft and caramelized, about 10-15 minutes. Remove from heat and stir in the chopped sage. Set aside.

Preheat your oven to 400°F (200°C). Season the filet mignon steaks generously with salt and freshly cracked black pepper on both sides.

In an oven-safe skillet, heat the remaining tablespoon of olive oil over high heat. Once hot, add the seasoned steaks and sear for 2-3 minutes on each side until a golden-brown crust forms.

Once the steaks are seared, remove the skillet from the heat. Top each steak with the caramelized shallot and sage mixture, spreading it evenly over the surface.

Transfer the skillet to the preheated oven and bake for 5-7 minutes for medium-rare, or adjust the time to your desired doneness.

Once cooked to your liking, remove the skillet from the oven. Let the steaks rest for a few minutes. Slice the chilled herb butter into rounds and place a slice on top of each filet mignon just before serving.

Garnish with additional fresh herbs if desired, and serve with your choice of side dishes.