In a large mixing bowl, using an electric mixer on medium speed, mix butter and sugar for 2 minutes. Add eggs one at a time, mixing between each addition.
Add corn, pumpkin puree, and cheeses. Mix until blended.
Add all dry ingredients and mix until combined.
In a greased 8x8'' or 9x9'' square pan, pour batter into the pan evenly.
Bake at 300 F for 1 hour and 15 minutes or 350 F for 50 minutes or until toothpick test comes out clean from the centre of the pan. Cool for at least 10 minutes before slicing.