Ingredients

• 4 heads bibb lettuce, separated in leaves
• 2 cups watercress, with stems cut short (about 1 bunch)
• 3/4 cup mild onion, very thinly sliced and separated in rings
• 1 cup sliced English cucumber (do not peel)
• 2 tablespoons salad oil
• 1 tablespoon tarragon vinegar
• 1/2 teaspoon Worcestershire sauce
• 3/4 teaspoon salt
• 1/4 teaspoon sugar
• freshly ground coarse black pepper