Cut the pumpkin into small cubes and place them into a pot. Squeeze out the juice of two oranges and pour over the pumpkin cubes. Cook together until the pumpkin becomes soft.
Separate the four eggs. Beat the egg yolks with 1/4 cup of sugar until stiff. Add the orange soda and oil to the mixture and then, using a sieve, add the flour and baking powder. Mix the ingredients together to form a batter.
Now beat the remaining egg whites with 1/4 cup of sugar, and fold the mixture into the batter.
Divide the batter into two equal portions. Add the cocoa and 1/2 cup milk to one portion of batter, and the pumpkin mash to the other. Mix well.
Alternating between each batter, spoon into the middle of a springform pan and let spread to the edges. In order to create a beautiful pattern, be sure to spoon the batter into the middle of the previous layer. Bake for 45-50 min at 300 °F.
Finally, melt the chocolate and pour over the cooled, finished product.
