Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 9-inch cake pan. Chill in freezer.
Cut kernels from ears of corn with a sharp knife. Beat butter in a large bowl with an electric mixer until smooth and creamy.
Combine eggs, condensed milk, whole milk, and corn kernels in a blender; blend until smooth. Transfer egg mixture to a bowl with butter and mix well.
Sift flour, baking powder, cinnamon, and salt into a large bowl. Add egg mixture and mix well to combine.
Remove cake pan from freezer. Grease and flour again. Pour batter into prepared pan.
Bake in the preheated oven until cake is golden brown and a toothpick inserted in the center comes out clean, about 45 minutes. Cool in the pan for 15 minutes, then remove from tin and cool on a wire rack.