Press zucchini between paper towels to remove excess moisture. Set aside.
Coat a large nonstick skillet with cooking spray; place over medium-high heat until hot. Add onion and garlic; saute 5 minutes or until tender. Add corn and carrot, and saute 5 minutes or until tender.
Combine 1/4 cup milk, flour, and cornmeal; stir well, and add to corn mixture in skillet. Cook, stirring constantly, until thickened and bubbly. Remove from heat.
Combine 1/2 cup milk, cottage cheese, and next 4 ingredients in container of an electric blender; cover and process until smooth. Add cottage cheese mixture to corn mixture; stir well. Stir in zucchini. Coat an 11- x 7- x 1 1/2-inch baking dish with cooking spray, and sprinkle with breadcrumbs. Spoon mixture into dish. Pour remaining 1/4 cup milk over mixture. Bake, uncovered, at 325° for 1 hour. Let stand 5 minutes before serving.