Place rack in the middle of oven and heat to 360 degrees F. Butter a 9 x12-inch pan.
In a mixer, beat the butter with sugar until creamy. Slowly add 8 egg yolks, one by one, until well incorporated. Add cream, all-purpose flour, rice flour and baking powder and continue beating until mixed.
In a blender, process the milk with corn kernels and incorporate it into the butter mix. Pour the mix in a big mixing bowl.
Separately, beat the egg whites with salt until stiff peaks are formed. Add 1/5 of the egg whites to the butter/corn mix and blend carefully. Slowly blend the rest until just mixed. Pour the corn batter into the baking dish.
Bake until it is springy to the touch and tanned, about 45 to 50 minutes. Once it cools a little, cut into squares. It can be served, warm, at room temperature or cold. It can be kept outside and covered for that day, or up to a week in the refrigerator. It's delicious served with creamed poblano rajas.
For creamed poblano rajas: To prepare the poblano peppers, char them for 6 to 9 minutes under the broiler, on a grill or on a cast-iron pan over medium heat, flipping sides in between. The skin should be charred and wrinkled (like marshmallows for s'mores!). Place them in a plastic bag and close it, so they will sweat for 10 to 15 minutes. Remove the poblanos from the bag, make a slit on their side, remove the stem and under a thin stream of water, peel their skin and remove the seeds. Cut the cooked and cleaned poblanos into strips.
Heat butter in a pan over medium-low heat. Once it begins to sizzle, sweat the slivered onion for about 10 minutes, until translucent and soft. Increase heat to medium-high, add chile poblano prepared as rajas or strips, salt and black pepper and cook for about 2 minutes.
Add cream and cheese and continue cooking, stirring from time to time, until the sauce thickens and seasons, for 6 to 8 more minutes. Serve hot. 10-12 servings.