3/4 pound beef flat iron steak or top sirloin steak
3/4 teaspoon salt, divided
1/2 teaspoon pepper, divided
1/4 cup olive oil
2 tablespoons balsamic vinegar
2 teaspoons lemon juice
5 ounces fresh baby spinach (about 6 cups)
1 medium beefsteak tomato, sliced
1/2 medium ripe avocado, peeled and sliced
4 radishes, thinly sliced
1/4 cup crumbled blue cheese, optional
Sprinkle steak with 1/2 teaspoon salt and 1/4 teaspoon pepper. Grill, covered, over medium heat or broil 4 in. from heat 6-8 minutes on each side or until meat reaches desired doneness (for medium-rare, a thermometer should read 135°; medium, 140°; medium-well, 145°). Let stand 5 minutes.
Meanwhile, in a small bowl, whisk oil, vinegar, lemon juice and the remaining salt and pepper. Divide spinach among four plates. Add tomato, avocado and radishes.
Cut steak into slices; place over salad. Drizzle with dressing; if desired, sprinkle with cheese.