In a food processer, blend basil leaves with two tablespoons of olive oil to make pesto spread.
Drizzle filets with olive oil, and dust with salt and pepper.
Turn on grill to medium heat and grill filets for 2 1/2 minutes per side to medium-rare.
Slice bread lengthwise and open up. Drizzle with olive oil. Slightly toast the rolls on grill and add cheese cooking till melted. Remove rolls, spread with a thick layer of pesto and tomatoes.
Add steak and top with the other half of roll. Cut in half and serve.