How to Make It
Preheat oven to 350°F. Toss baguette pieces with lemon zest, 1 tablespoon each of the oil and Parmesan, and ¼ teaspoon of the salt on a parchment paper-lined rimmed baking sheet. Spread in a single layer. Bake in preheated oven until golden and crispy, 14 to 16 minutes, tossing halfway through.
Whisk together yogurt, Dijon, garlic, lemon juice, and remaining 1 tablespoon oil and ½ cup Parmesan in a large bowl. Season with remaining ½ teaspoon salt and several grinds black pepper.
Toss lettuce with ½ cup of the dressing, adding more to taste. Divide among 4 plates, and top with croutons and more Parmesan. Reserve any remaining dressing as a dip for crudités or chips.