In a dry skillet over medium heat, toast the allspice berries and coriander seeds until fragrant, about 2-3 minutes. Remove from heat and let cool slightly. Once cooled, crush the spices using a mortar and pestle or a spice grinder.

Pat the filet mignon steaks dry with paper towels. Season both sides generously with salt and freshly ground black pepper. Press the crushed allspice and coriander mixture onto both sides of the steaks, ensuring an even coating.

In a large skillet, heat the olive oil over medium-high heat. Once hot, add the seasoned steaks. Sear for about 4-5 minutes on each side for medium-rare, or until your desired doneness is reached. Remove the steaks from the skillet and let them rest for 5 minutes.

In a small bowl, combine the softened butter, roasted garlic, minced shallots, chopped parsley, and lemon juice. Mix well until all ingredients are incorporated.

Slice the filet mignon and place on a plate. Top generously with the roasted garlic shallot butter, allowing it to melt over the warm steak. Serve immediately with your favorite sides.