Flank steak, tomato and watermelon salad

Ingredients

• 1 1/2 pounds flank steak
• 1/3 cup red wine vinegar
• 1/3 cup olive oil
• 1 T fresh rosemary, finely chopped
• Salt
• pepper
• 1/2 head romaine lettuce, washed and torn into pieces
• 1/2 head red leaf lettuce, washed and torn into pieces
• 2 cups watermelon, cut into 1″ cubes
• 1 1/2 cups cherry tomatoes, halved
• 1 avocado, peeled and sliced
• 1/2 cup red onion, thinly sliced
• 2 ounces of crumble blue cheese
• 2 T balsamic vinegar
• 4 T olive oil
• 1 T shallot, finely minced