Step 1

Preheat the oven to 350 degrees F. Grease and flour a 12-cup Bundt or tube pan.

Step 2

In a large bowl, cream together the cream cheese, butter, and shortening with an electric mixer on medium-high speed until light and fluffy, about 5 minutes. In a smaller bowl, combine the flour, baking powder, and salt. Add the flour mixture to the creamed mixture and mix on low speed until blended - it will be very thick.

Step 3

Gradually add 1 cup of the sugar and the eggs, one at a time, beating well after each addition. Add the vanilla and the remaining 1 cup sugar and continue beating, scraping down the sides of the bowl once or twice, until the batter is smooth.

Step 4

Pour half of the mixture into the prepared pan. Top with the melted chocolate and swirl a knife through the batter to marble it. Top with the remaining batter.

Step 5

Bake for 60 to 65 minutes, or until a toothpick inserted in the center comes out clean. Cool on a wire rack for 15 minutes. Invert the cake onto a platter and cool completely. Before serving, dust with a generous amount of confectioner's sugar.