Beat butter in a medium bowl with an electric mixer until creamy. Beat masa harina and water into creamed butter until smooth.
Place 1 cup corn in a blender; blend until smooth. Stir blended corn, remaining 1 cup corn, and cornmeal into masa harina mixture.
Mix sugar, cream, baking powder, and salt together in a separate bowl. Pour sugar mixture into corn mixture; stir to combine. Spoon corn batter into an ungreased 8-inch square baking dish. Smooth the top of the batter with a spatula. Cover dish with aluminum foil.
Fill a 9x13-inch casserole dish 1/3 full of hot water. Place the covered 8-inch square dish into the water.
Bake in the preheated oven until a toothpick inserted in the center of the cake comes out clean, 50 to 60 minutes. Remove 8x8-inch dish from water bath and let cool for 10 minutes.