Ideal slow cooker size: 3-Quart, or bake in a loaf pan placed inside a 6-Quart.
In a mixing bowl, whisk together the cornmeal, flour, baking powder, salt and sugar until well combined.
In another bowl beat the egg well, then add the milk and melted butter. Mix until well blended.
Pour the egg mixture into the cornmeal mixture. Stir just until mixed.
Pour into greased slow cooker (3-Quart). Or if you only have a large slow cooker, pour into a greased baking pan and place the pan inside your slow cooker. (I used a loaf a pan inside my 6-Quart oval slow cooker.)
Cover and cook on HIGH for 1-1/2 to 2-1/2 hours, or until a tester inserted in the center comes out clean.