Preheat oven to 350°F. Cut tips off corn and discard. Stand corn upright in a large bowl. Scrape kernels, liquid, and pulp from cobs into bowl; discard cobs. Add milk, eggs, sugar, flour, and salt. Whisk just until blended. Pour butter into a 2-quart baking dish, swirling to coat bottom and sides. Pour corn mixture into dish.  Bake until lightly browned, 1 hour to 1 hour and 10 minutes.