Place the steak in a baking dish. Pour the marinade over and turn to thoroughly coat. Let stand at room temperature for 1 hour, turning once or twice.
On a stovetop preheat a large skillet over medium heat. Add the oil and butter. When the butter is melted and bubbling add the shallots and cook until they begin to soften, about 5 minutes, stirring frequently. Add the vinegar, thyme, salt, and black pepper, reduce the heat to medium-low, and continue to cook until the shallots are golden brown and beginning to caramelize, about 25 minutes, stirring occasionally. Remove from the heat and keep warm while you grill the potatoes and steak.
Prepare the grill for direct cooking over medium-high heat (450° to 500°F).
Prepare the grill for cooking over medium-high heat (500°F).
Cut the potatoes in half lengthwise, then cut each half lengthwise into (1/2 inch) thick
wedges. Place the wedges in a bowl. Add the oil, salt, garlic powder, paprika, and black pepper and toss to coat.
Arrange the wedges on the grill perpendicular to the grates. Grill over direct medium-high heat, with the lid closed, until well-marked, golden brown, and tender, 15 to 20 minutes, turning every 4 to 5 minutes.
Arrange the wedges on the grill perpendicular to the grates. Grill over medium-high heat, with the lid closed, until well-marked, golden brown, and tender, 15 to 20 minutes, turning every 4 to 5 minutes.
While the potatoes are cooking, remove the steak from the marinade, letting any excess marinade fall back in the baking dish. Grill the steak over direct medium-high heat, with the lid closed, until an instant-read thermometer inserted into the center of the steak registers 125°F, 6 to 8 minutes for medium rare (or your preferred doneness), turning once. Remove from the grill and rest at room temperature, indoors, for 10 minutes.
While the potatoes are cooking, remove the steak from the marinade, letting any excess marinade fall back in the baking dish. Grill the steak over medium-high heat, with the lid closed, until the center of the steak registers 125°F, 6 to 8 minutes for medium rare (or your preferred doneness), turning once. Remove from the grill and rest at room temperature, indoors, for 10 minutes.
Thinly slice the steak on the diagonal across the grain. Arrange the steak on serving plates and drizzle with any accumulated meat juices. Serve with the shallots and steak fries.
