Bring the vinegar to a rapid simmer in a small saucepan over medium heat. Reduce the heat to medium-low and cook at a low simmer, stirring occasionally, until the vinegar is thick enough to coat the back of a metal spoon, about 15 minutes. Remove from the heat and let cool.

Place the vegetable oil into a hot skillet over medium-high heat. Season the steak with salt and pepper and cook to the desired level of doneness, flipping the steak halfway through the cooking time. Remove the steak from the skillet and set aside.

Prepare an alfredo sauce: Warm the butter and heavy cream in a medium saucepan over medium heat until it just begins to bubble. Add the Parmesan cheese and garlic powder and stir continuously until the cheese melts. Reduce the heat to low and simmer until the sauce reduces.

To assemble the dish, place the prepared pasta into a mixing bowl and toss with the spinach. Add the alfredo sauce and mix well. Transfer to a broiler-safe serving plate. Place portions of the steak over the pasta and top with the sundried tomatoes and Gorgonzola. Place the dish under the broiler until the cheese just begins to brown. Drizzle the balsamic reduction over the steak just before serving.