Step 1: Prepare the Steak

1. Butterfly the steak: Lay the flank steak on a cutting board. Using a sharp knife, carefully slice the steak horizontally, starting from one long edge and cutting almost all the way through, leaving about ½ inch uncut. Open the steak like a book to create a larger, thinner piece of meat.
2. Pound the steak: Place a sheet of plastic wrap over the steak and use a meat mallet to pound it to an even thickness of about ¼ inch. This ensures the steak cooks evenly and is tender.
3. Season the steak: Remove the plastic wrap and season both sides of the steak with salt, black pepper, and garlic powder.

Step 2: Prepare the Filling

1. Sauté the spinach: Heat a small skillet over medium heat with 1 teaspoon of olive oil. Add the chopped spinach and minced garlic. Sauté for 2-3 minutes, or until the spinach is wilted and fragrant. Remove from heat and let cool slightly.
2. Combine the filling ingredients: In a mixing bowl, combine the sautéed spinach, mozzarella, parmesan, oregano, basil, and red pepper flakes. Mix well.

Step 3: Assemble the Pinwheels

1. Spread the filling: Lay the prepared steak flat on the cutting board with the grain of the meat running horizontally. Spread the spinach and cheese filling evenly over the surface of the steak, leaving about 1 inch of space along the edges to prevent overflow.
2. Add the roasted red peppers: Lay the thinly sliced roasted red peppers over the spinach and cheese mixture in an even layer.
3. Roll the steak: Starting from one of the long edges, tightly roll the steak into a log. Make sure the roll is firm but not so tight that the filling spills out.
4. Tie the steak roll: Use kitchen twine to tie the rolled steak at 2-inch intervals, securing the shape and ensuring the filling stays in place.

Step 4: Sear and Cook the Pinwheels

1. Preheat the oven: Preheat your oven to 375°F (190°C).
2. Sear the steak roll: Heat 1 tablespoon of olive oil in an oven-safe skillet over medium-high heat. Sear the steak roll on all sides for about 2-3 minutes per side, until browned.
3. Bake the pinwheels: Transfer the skillet to the preheated oven and bake for 15-20 minutes, or until the steak reaches your desired level of doneness (130°F for medium-rare or 140°F for medium).
4. Rest the steak: Remove the steak roll from the oven and let it rest on a cutting board for 5-10 minutes. This allows the juices to redistribute and keeps the meat tender.

Step 5: Slice and Serve

1. Slice the pinwheels: Use a sharp knife to carefully slice the steak roll into 1-inch thick pinwheels. Cut between the twine, then remove the twine from each piece before serving.
2. Garnish and serve: Arrange the pinwheels on a serving platter and garnish with fresh parsley and shaved parmesan cheese. Serve immediately with your favorite sides.