cucumber, peeled, seeded, and cut into 1/2-inch dice
1 medium
red bell pepper, cut into 1/2-inch dice
2
celery stalks, cut into 1/2-inch dice
3
radishes, cut into 1/2-inch dice
1 small
red onion, finely chopped
1 tbsp
white wine vinegar
Instructions
STEP 1
1 Combine the steak, mustard, 1 teaspoon of the oil, and the rosemary in a medium bowl.,
STEP 2
2 Heat a grill pan over medium heat until hot.,
STEP 3
3 Season the steak with 1/4 teaspoon of the salt and 1/8 teaspoon of the pepper, and add it to the pan: Cook for 4 to 5 minutes per side or medium-rare, or to desired doneness.,
STEP 4
4 Transfer to a cutting board and let stand for 5 minutes.,
STEP 5
5 While the steak rests, combine the lettuce, cucumber, bell pepper, celery, radishes, onion, vinegar, and the remaining 4 teaspoons oil, 1/4 teaspoon salt, and 1/8 teaspoon pepper in a separate bowl.,
STEP 6
6 Cut the steak diagonally across the grain into thin slices. Divide the salad between two plates, and top it with the steak.