How to Make It
Step 1
Heat a grill pan over medium-high heat. Sprinkle steak with salt and pepper. Add steak to pan, and cook 2 1/2 minutes on each side or until desired degree of doneness. Remove the steak from pan, and let stand 5 minutes. Cut steak across grain into thin slices.
Step 2
Combine mayonnaise and pesto, stirring until well blended. Spread mayonnaise mixture evenly over cut sides of bread. Layer bottom half of bread with arugula, red onion, steak, and tomato; top with top half of bread. Cut sandwich diagonally into 4 equal pieces.
