I saw a picture of something similar a few weeks ago and decided to make my own version. This recipe takes a little bit of effort but it's totally worth it for the stunning presentation that is sure to impress all your guests.
Butterfly the steak by slicing through it horizontally, leaving halves attached by 1/2 inch. Open and flatten the meat and lightly salt and pepper. Pound the meat to get an even thickness and set aside.
Combine the oil, onion, peppers and garlic in a saute pan and cook until the vegetables are soft and get a little bit of color. Let the mixture cool slightly, then add the chopped herbs and lightly salt and pepper to taste.
Spread the stuffing mixture over the opened steak. Roll up the steak tightly lengthwise. Tie the rolled steak up with butcher's twine about every 3-4 inches. Lightly season the outside of the steak with salt and pepper.
Place the steak on the grill over medium-high heat and turn to brown on all sides, cooking until the internal temp is about 125-130 degrees, about 25 minutes. If you prefer your steak with no pink, you can leave it on for an additional ten minutes.
Remove the steak from the grill and let it rest for roughly ten minutes. Slice into 1/2" pieces and serve.