Preheat oven to 350°F. Put pulp and sugar into large mixing bowl. Mix well. Beat in eggs. Put buttermilk and baking soda into a small bowl and stir. Add to pulp, and mix well.

Sift together flour, baking powder, cinnamon, salt into a med. bowl. Gradually add to pulp, stirring til well combined. Add heavy cream and mix well.

Grease a 9x13 inch baking dish with some of the butter. Stir the remaining butter into the batter.

Pour batter into dish. Bake til dark brown and toothpick inserted into center comes out clean, about 1 hour. Set aside to cool. Serve with whipped cream if you like.