Preheat oven to 350 degrees.
Blend butter in a medium bowl with an electric mixer until creamy.
Add the masa harina and water to the butter and beat until well combined.
Put defrosted corn into blender or food processor and with short pulses, coarsley chop the corn on low speed. You want to leave several whole pieces of corn.
Stir the chopped corn into the butter and masa harina mixture. Add cornmeal to the mixture and combine.
In another medium bowl, mix together the sugar, cream, salt, and baking powder. When the ingredients are well blended (NOTE: It turns out much better if you blend till it's thick & creamy), pour the mixture into the other bowl and stir everything together BY HAND.
Pour corn batter into an ungreased "8x8" baking pan. Cover the pan with aluminum foil. Place this pan into a "9x13" pan filled 1/3 of the way up with hot water. Bake for 50-60 minutes or until the corn cake is cooked through. When the corn cake is done, remove the small pan from the larger pan and let sit for at least 10 minutes.
To serve, scoop out each portion with an ice cream scoop or rounded spoon(NOTE: 1/4 or 1/3 measuring cup works great, press "cake" in cup to form before placing on plate) .