Cream together butter and sugar. Add in eggs and heavy cream.
Next blend in flour, baking powder, and salt. Fold in fresh cranberries.
Grease an angel food cake pan and preheat oven to 350 °F.
Pour batter into greased pan and spread out the top evenly. It is a thick batter and needs to be baked even. Bake for 60 minutes or until toothpick comes out clean.
Remove cake from pan and let sit out on wire rack to cool completely. Whip up all the frosting ingredients together and pipe on top when cake is cold.