This turkey burger is a healthy version of the American classic that's simple and quick to make.
Heat the broiler to high. In a large bowl, combine the turkey, zucchini, carrot, garlic, thyme, salt, pepper and egg. Form the mixture into 4 patties.
Heat 1 tablespoon of the oil in a large skillet over medium heat. Cook the patties, turning once, until no trace of pink remains, about 4-5 minutes per side.
Meanwhile, place the bread on a baking sheet and brush with the remaining oil. Broil until golden brown and crisp, about 1½ minutes. Transfer the bread to individual plates. Top with lettuce leaves and burgers. If using, combine mayonnaise and lemon juice in a small bowl, and serve with the burgers.