Via Carota's Green Salad

Name: Via Carota's Green Salad
Prep time: 35 min
Total time: 35 min
Cuisine: Italian
Ingredients: 1 clove shallot (very finely chopped); 1 small clove garlic (grated or very finely minced); 1/2 teaspoon granulated sugar; 1/2 teaspoon Diamond-Crystal Kosher Salt (or 1/4 teaspoon salt if using any other type of salt); 2 tablespoons aged sherry vinegar; 1 teaspoon whole-grain mustard (optional); 1 teaspoon warm water; 3 sprigs fresh thyme (stripped); 6 tablespoons extra-virgin olive oil (divided); Black pepper; 1 head butter lettuce (such as Bibb or Boston lettuce, about 3 - 4 ounces); 1 head baby romaine (about 6 ounces, or a regular romaine heart or little Gem lettuce); 1/2 small head frisée (about 2 ounces, see notes); 3 spears Belgian endive; A small handful of watercress (or peppercress or arugula, about 1/2 ounce); Salt and black pepper