Meanwhile, rinse and set the 2 large leaves of green leaf lettuce aside. Chop the 1 cup of broccoli, 1 cup of purple onion, and 1/2 cup of tomatoes. Add them to a frying pan on a medium/high heat along with the 2 tbsp of olive oil, 1/4 tsp of sea salt, and 1/2 tsp of black pepper. Cook until vegetables are tender, about 10 minutes.