Preheat your oven to 400°F (200°C).

In a small bowl, combine the crushed dried cherries and crushed black peppercorns. Season the filet mignon steaks with salt, then press the cherry-peppercorn mixture onto both sides of each steak, ensuring an even coating.

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

Transfer the skillet to the preheated oven and cook for an additional 5-7 minutes for medium-rare, or until your desired doneness is achieved. Remove the steaks from the oven and let them rest for about 5 minutes.

While the steaks are resting, prepare the caramelized onion gravy. In the same skillet, reduce the heat to medium and add the butter. Once melted, add the sliced onions and cook, stirring occasionally, until they are soft and caramelized, about 15-20 minutes.

Stir in the beef broth and balsamic vinegar, scraping up any browned bits from the bottom of the skillet. Allow the mixture to simmer for about 5 minutes, until slightly thickened. Adjust seasoning with salt as needed.

To serve, place each filet mignon on a plate and spoon the caramelized onion gravy over the top. Garnish with fresh thyme.