Preheat oven to 325 degrees and grease an 8x8 inch square baking dish.
Place the butter, masa and sugar in a medium mixing bowl and combine using an electric mixer until light and fluffy, about 1 minute. Set aside.
Place half the corn kernels and water in a blender (or food processor) and puree until smooth.
Add the pureed corn to the butter mixture and stir well to combine.
Add in the remaining corn kernels, corn meal, baking powder, salt and milk and mix with a spoon or rubber spatula until everything is combined.
Pour the mixture into the 8x8 inch baking dish and cover tightly with aluminum foil. Place the dish into a large roasting pan and fill up the roasting pan with water until it comes about ⅔ of the way up the side of the 8x8 inch dish.
Place the roasting pan (with corn dish) into the oven and bake for about 1 - 1½ hours; you want everything to be firm and cooked through, but not dry.
Remove from oven and allow to cool for about 10 minutes.
Use an ice cream scoop to serve.