Combine the lettuce, chicken, tomatoes, and onion in a bowl.
1 large head of butter lettuce, 2 chicken breasts, 3 small tomatoes, ½ red onion
To prepare the vinaigrette, simply whisk together the olive oil, vinegar, and mustard. Add the thyme and oregano, then season to taste.
¼ cup extra-virgin olive oil, 2 tbsp. balsamic vinegar, 2 tsp. Dijon mustard, 2 pinches of dried thyme, 2 pinches of dried oregano, Sea salt and freshly ground black pepper
Serve the salad with the vinaigrette right before eating.