1. Pat steak dry with paper towels and season with 1/2 teaspoon of the salt and pepper. Heat oil in large skillet over medium heat. Place steak in skillet and cook, without moving, until well browned, about 3 to 5 minutes. Flip steak and cook on second side until well browned, about 4 more minutes for medium doneness - this particular cut of steak is best at medium or medium rare. Transfer steak to a plate and cover with foil.
2. Keeping the heat on medium, add onion and 1/4 teaspoon of the salt. Cook, stirring frequently, until onions are lightly browned, about 8 to 10 minutes.
3. Increase heat to medium-high. Add vinegar, water, Worcestershire sauce, and brown sugar and cook, scraping up browned bits with a wooden spoon until thick and syrupy, about 2 to 4 minutes. Pour any accumulated juices from steak into pan.
4. To assemble, slice steak crosswise into 1/4-inch-thick slices, trimming any fat or gristle. Divide steak evenly over bottom half of each baguette, spoon onion on top, and scatter Gorgonzola over onion. Cover with top half of bread, cut baguette in half, and serve.
Source: Hannaford fresh Magazine, September - October 2007