Onion Tart with Green Salad

Name: Onion Tart with Green Salad
Ingredients: 3 tablespoons butter; 1 large sprig thyme; 3 tablespoons sugar; 3 onions, medium sized, tips removed, skin left on and cut in half widthwise; 1 sheet puff pastry; 1 egg; 1 tablespoon water; Green Salad, recipe follows; 1/2 cup aged red wine vinegar; 2 tablespoons minced shallots; 1 tablespoon salt; 1 tablespoon fresh ground black pepper; 2 tablespoons Dijon mustard; 1 1/2 cups extra-virgin olive oil; 2 heads green and red leaf lettuces (or your preference); 1 cup French green beans, blanched; 6 radishes, cleaned and quartered; 12 spears asparagus, blanched; 12 baby carrots, peeled and blanched