Prepare campfire or grill for low heat, using 32-40 charcoal briquettes., Line the inside of a 10-in. Dutch oven with heavy-duty foil. In a large bowl, whisk together first 4 ingredients. Add milk and melted butter, stirring just until moistened. Pour into prepared pan., Drain peaches, reserving 1 cup syrup. Arrange peaches over batter; sprinkle with sugar and, if desired, cinnamon. Pour reserved syrup over fruit. Place lid on Dutch oven., When briquettes are covered with white ash, place Dutch oven directly on half of the briquettes. Using long-handled tongs, place remaining briquettes on top of pan lid. Cook 30-40 minutes or until cobbler is set and beginning to brown, using tongs to lift lid carefully when checking. If necessary, cook 5 minutes longer. Remove from heat; let stand, uncovered, 15 minutes before serving.