In a large saucepan, cook zucchini in boiling water until crisp-tender, about 4 minutes; drain. Cool for 10 minutes. In a large bowl, combine the flour, baking powder and salt; whisk in milk until smooth. Beat in eggs and chilies. Stir in cheese and zucchini.
Transfer to a greased 13x9-in. baking dish. Toss bread crumbs and butter; sprinkle over zucchini mixture. Bake, uncovered, at 325° for 40-50 minutes or until a knife inserted in the center comes out clean and edges are lightly browned. Let stand for 5 minutes before cutting.