• Preheat your oven to 356°F / 180°C.
• Generously grease an 8-inch (22 cm) Bundt pan or tube pan with butter, then dust lightly with flour or breadcrumbs to prevent sticking.
• In a large bowl, beat the butter, sugar, and vanilla extract with a stand or hand mixer until light and creamy, about 3-4 minutes.
  1 cups butter , 1 cups granulated sugar , 2 teaspoon vanilla extract
• Add the eggs one at a time, beating for approximatley 30 seconds after each addition. Mix in the heavy cream.
  5 eggs , ¾ cup whipping cream
• Sift the flour, baking powder, and salt into the mixture. (Sifting creates a lighter, airier cake.) Fold or mix until just combined. (overmixing will cause the cake to become dense)
  2 ½ cups all-purpose flour, 3 teaspoon baking powder , 1 pinch salt
• Pour two-thirds of the batter into your prepared pan.
• Sift the cocoa powder to the remaining batter and mix until evenly brown.
  3 tablespoon unsweetend cocoa powder
• Spoon or pour the chocolate batter over the vanilla batter. Using a knife or skewer, swirl through the batters in a figure-eight or spiral motion to create marbling—don't overmix!
  
• Bake for 45-50 minutes, until a toothpick or skewer inserted into the center comes out clean or with just a few moist crumbs.
• Let the cake cool in the pan for 10 minutes, then turn out onto a wire rack to cool completely.

To decorate

• Once cooled either dust with powdered sugar or drizzle with melted dark chocolate glaze.
  2 table spoons icing sugar /confectioners sugar , 1 pack dark chocolate glaze