- Preheat the oven to 375°F. 
- Lay the flank steak flat on a cutting board and pound it to an even thickness using a meat mallet. 
- In a mixing bowl, combine the spinach, ricotta cheese, Parmesan cheese, sun-dried tomatoes, basil, garlic, salt, pepper, and Italian seasoning. Mix until well combined. 
- Spread the filling evenly over the flank steak, leaving a small border around the edges. 
- Starting from one end, tightly roll the steak up around the filling. 
- Secure the roll with kitchen twine or toothpicks at intervals. 
- Heat the olive oil in a large oven-safe skillet over medium-high heat. 
- Sear the stuffed flank steak on all sides until browned, about 3-4 minutes per side. 
- Transfer the skillet to the preheated oven and bake for 25-30 minutes, or until the internal temperature reaches 145°F for medium-rare. 
- Remove from the oven and let rest for 10 minutes before slicing. Serve warm.