01 - Remove the filet mignon from the refrigerator 30 minutes prior to cooking to allow it to reach room temperature. Thoroughly pat the steaks dry with paper towels.
02 - Preheat your oven to 400°F.
03 - Generously season both sides of the steaks with kosher salt and freshly ground black pepper.
04 - Heat 1 tablespoon of olive oil in a heavy oven-safe skillet (such as cast iron) over medium-high heat until shimmering.
05 - Carefully place the seasoned steaks in the hot skillet. Sear for 2 to 3 minutes per side until a rich, golden-brown crust develops.
06 - Add 1 tablespoon of unsalted butter to the skillet. As the butter melts, spoon it repeatedly over the searing steaks to baste them.
07 - Transfer the skillet with the steaks to the preheated oven. Roast for 5 to 7 minutes for a medium-rare doneness (internal temperature of 130°F), or adjust cooking time to achieve your preferred level of doneness.
08 - Remove the skillet from the oven and carefully transfer the cooked steaks to a clean plate. Tent loosely with aluminum foil and allow them to rest for 5 minutes. This step is crucial for juicy steaks.
09 - While the steaks are resting, combine 1/2 cup of balsamic vinegar, 2 tablespoons of honey, and the optional 1 teaspoon of finely chopped fresh rosemary in a small saucepan. Bring the mixture to a gentle boil over medium heat, then reduce the heat to a simmer. Cook for 6 to 8 minutes, stirring occasionally, until the reduction has thickened to a syrupy consistency and has reduced by half.
10 - Arrange the rested filet mignon on serving plates. Drizzle generously with the warm balsamic reduction. If desired, garnish with fresh rosemary sprigs or microgreens before serving.