1
Preheat a well-oiled grill to medium-high heat. (TIP: If using a grill pan, you’ll heat it in Step 2.) Wash and dry produce.
Dice potatoes into ¾-inch pieces. Place in a medium pot with enough salted water to cover by 2 inches. Bring to a boil and cook until fork-tender, 10-12 minutes. Drain and rinse under cold water; transfer to a large bowl and let cool completely. TIP: Spread potatoes out around edges of the bowl to help them cool more quickly.
While potatoes cook, slice baguette crosswise into 8 rounds (16 rounds for 4 servings). Quarter tomatoes. Roughly chop parsley. Zest and quarter lemon (for 4, zest one lemon and quarter both). Trim and discard root end from lettuce; roughly chop leaves.