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Tunnel of Mousse Cake

Tunnel of Mousse Cake

Who doesn’t love a chocolate mousse cake? But even better is a Tunnel of Mousse Cake with mousse utilized as both frosting and filling!


For Cake:

For Mousse:


  1. Preheat oven to 325º.
  2. Put cocoa powder into small bowl and stir in the boiling water till smooth. Cool for 30 minutes. Sift together flour, sugar, soda and salt. Make a well in the center and add oil, egg yolks, vanilla and cocoa mixture. Beat till smooth with a hand mixer, scraping sides of bowl as needed. Set aside.
  3. Put egg whites into the bowl of a stand mixer fit with the whisk attachment. Sprinkle with cream of tartar. Beat until stiff peaks form. Pour chocolate batter over egg whites and gently fold together till blended. Pour into an ungreased tube pan.
  4. Bake for 50-60 minutes or till the top of the cake springs back when pressed. Cool on rack for at least 1½ hours. Use a straight, thin metal spatula to go around the perimeter of the cooked cake to help loosen, then remove carefully.
  5. Make the mousse by combining all ingredients. Refrigerate for one hour. Then beat till quite firm. Refrigerate for another hour before assembling the cake.
  6. When whipped mousse is fully chilled, prepare the cake. With a long serrated knife, carefully slice off the top 1 inch of the cake. As a guide, insert toothpicks one inch below the top spaced around the perimeter. Reserve the top for later.
  7. Next cut vertically around the perimeter of the cake, one inch from the outside edge and one inch from the inside edge. You will be making a well in the middle of the cake. Be careful not to cut through to the bottom of the cake. Carefully cut the inside into sections and pull out pieces of the cake leaving one inch of cake at at the bottom for the base. Reserve cake pieces.
  8. Fill the cavity with the chilled mousse. Crumble some of the reserved cake into a bowl and mix in ½ cup of mousse. Fill the hole in the center of the cake with the mousse/cake mixture.
  9. Replace the top of the cake and frost with the remaining mousse. Garnish as desired. Refrigerate leftovers.


Snack on leftover cake pieces.

Total time does not include cooling time.