Balsamic Filet Mignon with Caramelized Onions

Prepare your steaks by sprinkling a blend of seasoned salt and black pepper evenly across both sides. Arrange them in a single layer within a large baking dish. In the meantime, combine olive oil, balsamic vinegar, mustard, and fragrant rosemary in a bowl. Whisk the ingredients together until well combined, then pour the mixture over the steaks, ensuring they are fully coated. Allow the meat to marinate for up to 30 minutes.

During this time, melt butter in a skillet over medium heat. Cook sliced onions in the melted butter until they become tender, then stir in sugar to enhance their flavor. Continue cooking until the onions achieve a deep caramelized state, setting them aside for later use.

Preheat your grill to high heat on one side and medium heat on the other side. Lightly brush the grill grate with oil to prevent sticking. Place the steaks on the hot side of the grill, cooking for 10 minutes and flipping once. When the steaks are almost cooked through, transfer them to the cooler side of the grill. Top each filet with a quarter of the caramelized onions and crumbled blue cheese, then close the lid. Continue cooking until the cheese is melted, allowing the flavors to meld together.