Decadence knows no bounds here!
In a large mixing bowl, combine flour, cocoa powder, baking powder, and salt. In a separate bowl, mix together butter, sugar, vanilla, eggs, sour cream, and vegetable oil.
Add dry ingredients to wet and mix until batter is smooth. Fold in 86 grams dark chocolate and 86 grams white chocolate. Pour the cake batter into the springform pan. Cover with foil.
Pour two and a half cups (600 milliliters) water into the multi-cooker. Insert steamer. Place the springform pan on top of the steamer rack. Close and lock lid. Close vent. Set to Pressure Cook on high for 50 minutes. Once cooking has finished, allow the steam to release naturally.
Carefully remove the springform pan from multi-cooker and remove foil immediately. Refrigerate for 15 to 20 minutes.
Release the cake from the springform pan and decorate with raspberries. Shave the remaining chocolate pieces using a vegetable peeler, then use shavings to garnish cake. Sprinkle with icing sugar and serve.