Preheat your grill or grill pan over medium-high heat.
Lay the thin slices of flank steak flat on a cutting board. Season both sides with salt and pepper.
On one end of each steak slice, place a few spinach leaves and a strip of roasted red pepper.
Roll the steak tightly around the filling, starting from the edge with the peppers and spinach. Secure each roll with a toothpick to hold it together.
In a small bowl, combine the balsamic glaze, olive oil, and minced garlic. Mix until well combined.
Brush the balsamic mixture generously over the steak rolls.
Place the steak rolls on the grill and cook for about 4-5 minutes per side, or until the steak is cooked to your desired doneness and has nice grill marks.
Once cooked, remove the rolls from the grill and let rest for a couple of minutes before carefully removing the toothpicks.
Drizzle any remaining balsamic glaze over the rolls for added flavor.
Garnish with fresh basil leaves before serving.
Notes
Let the rolls rest before removing toothpicks for easier serving.