Remove the skin and seeds from the sweet pumpkin, then steam it.
Mash the steamed pumpkin until smooth.
Melt the chocolate over a double boiler.
Mix the mashed pumpkin with the melted chocolate, eggs, and sugar.
Sift in the flour and baking powder, then combine.
Pour the batter into a cake mold and spread evenly.
Bake in a 170°C oven for 30–35 minutes.
Let the cake cool, then decorate as desired.