Preheat oven to 400°F (200°C). Grease 9 x 13-in. (3 L) baking dish. In bowl, combine breadcrumbs, cheese, garlic, lemon zest, thyme, salt and pepper.
Arrange slightly overlapping tomatoes slices in single layer in prepared baking dish. Top with breadcrumb mixture.
Bake 15 to 20 min., or until breadcrumbs are golden, cheese is melted and tomatoes are tender.
Instead of tomatoes, use 2 zucchinis, sliced ¼-in. (5-mm) thick.