In a skillet, melt 2 tablespoons of butter over medium heat. Add the finely sliced leeks and cook until they are soft and golden brown, about 8-10 minutes. Stir in the breadcrumbs and cook for an additional 2-3 minutes until the mixture is crispy. Remove from heat and set aside.

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

In an oven-safe skillet, heat 1 tablespoon of olive oil over medium-high heat. Once hot, add the seasoned filet mignon and sear for 3-4 minutes on each side until a golden crust forms.

Remove the skillet from heat. Spread the mashed black garlic evenly over the top of each filet. Press the crispy leek and breadcrumb mixture firmly onto the garlic-covered steaks to form a crust.

Transfer the skillet to the preheated oven and bake for an additional 6-8 minutes for medium-rare, or until your desired doneness is reached.

In a small bowl, combine the remaining 2 tablespoons of softened butter, chopped sun-dried tomatoes, fresh parsley, thyme leaves, and balsamic vinegar. Mix until well combined.

Once the filet mignon is done, remove it from the oven and let it rest for 5 minutes. Top each steak with a generous dollop of sun-dried tomato confit butter before serving.