Grilled Stuffed Flank Steak

Preparation

1. In a small saute pan, drizzle 1 tsp olive oil, and place over medium-high heat. Add the onion and stir, reducing the heat once it starts to sizzle. Cook for 10 minutes, stirring occasionally. While the onions cook, place spinach in a microwave-safe container and cook on high for 1 to 2 minutes, then pat or roll with paper towels until completely dry. Add spinach, 1/4 tsp salt and thyme to the onions and stir. Let cool completely, then add the blue cheese. Reserve.
2. To butterfly the steak, place the meat on a cutting board with the grain running perpendicular to the edge of the counter and use a chef’s knife to cut a mark along one side of the steak that divides the edge into two even sections. Holding your knife parallel to the cutting board, slice the steak into two even layers, leaving the final edge uncut. Open the steak like a book and press the meat flat. Sprinkle with about half of the remaining salt and pepper. Spread the spinach and cheese mixture over the steak, leaving about an inch bare at the long edges. Roll the steak, with the grain going the length of the roll, holding the filling inside. Tie several pieces of string around the circumference of the roll to keep it closed.
3. Preheat gas grill to high heat. Brush the outside of the roll with the remaining 2 tsp olive oil, and sprinkle with remaining salt and pepper. Place on grill, browning on each of the 4 sides for 2 minutes. Turn off one burner and lower the others so the temperature stabilizes at 400°F. Cook over indirect heat for about 30 minutes or until internal temperature of steak reaches 135 to 140°F. for medium rare or 140 to 145°F. for medium. Remove steak from the grill and cover loosely with foil. Let stand for 10 minutes, then slice and serve.