Bring milk to a simmer in a medium saucepan over medium heat, stirring frequently with a whisk. Gradually whisk in cornmeal and salt. Simmer 3 minutes or until mixture thickens, stirring frequently with a whisk. Remove from heat. Combine buttermilk and next 3 ingredients; add to cornmeal mixture, stirring until well blended. Stir in corn.
Coat a 2-quart baking dish with cooking spray. Pour batter into dish.
Bake at 400° for 40 minutes or until puffed and golden, and a wooden pick inserted in center comes out clean. Serve warm.