In a bowl, combine the softened unsalted butter and smoked bone marrow. Mix until well incorporated. Add salt and pepper to taste, and a pinch of smoked paprika if desired. Shape the mixture into a log using plastic wrap and refrigerate until firm.

Preheat your oven to 400°F (200°C). Season the filet mignon steaks with salt and pepper on both sides. In a food processor, pulse the toasted sunflower seeds, crushed coriander seeds, blackened onion powder, and smoked paprika until a coarse crumb forms. Press the sunflower seed mixture onto both sides of each filet mignon to create a crust.

Heat a skillet over medium-high heat and add a drizzle of oil. Once the oil is hot, add the coated filet mignon steaks. Sear for about 3-4 minutes on each side, or until a golden-brown crust forms.

Transfer the skillet to the preheated oven and bake for an additional 5-7 minutes for medium-rare, or until desired doneness is reached. Use a meat thermometer for accuracy; 130°F (54°C) is medium-rare.

Remove the steaks from the oven and let them rest for 5 minutes. Slice the compound butter into rounds and place a piece on top of each steak just before serving. Garnish with fresh chopped parsley.