Preheat grill to medium-high heat using both burners.
Mash together butter, sun-dried tomatoes, basil, parsley and garlic in a bowl using a fork until blended together. If using unsalted butter, season with salt.
Grill steaks, 5 minutes per side for medium-rare, longer for desired doneness, remove from grill and tent with foil and rest for 5 minutes. Serve steaks topped with tomato butter.