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

In a small bowl, combine the toasted coriander seeds and preserved lemon zest. Mix well to combine.

In a large oven-safe skillet, heat the olive oil over medium-high heat. Once hot, add the filet mignon steaks. Sear the steaks for about 3-4 minutes on each side, or until a nice brown crust forms.

Remove the skillet from heat. Press the coriander and lemon zest mixture onto the top of each filet mignon, ensuring an even coating.

Transfer the skillet to the preheated oven and bake for about 5-7 minutes for medium-rare, or until your desired level of doneness is reached. Use a meat thermometer for accuracy (130°F for medium-rare).

While the steaks are baking, melt the butter in a saucepan over medium heat. Allow it to cook until it turns a golden brown and has a nutty aroma, about 4-5 minutes. Add the minced garlic and cook for an additional minute until fragrant.

Stir in the beef broth and balsamic vinegar, scraping up any browned bits from the pan. Let it simmer for about 5 minutes until slightly reduced. Stir in the chopped tarragon just before serving.

Once the steaks are done, remove them from the oven and let them rest for 5 minutes. Plate the filet mignon and drizzle the brown butter tarragon reduction over the top. Serve immediately.