Chocolate & Strawberry Mousse Cake

For the cake:
Preheat oven to 350 F. Grease and flour a 9″ x 13″ baking pan.

In a large bowl, mix together sugar, flour, cocoa powder, baking powder, baking soda and salt. Crack in the egg, spoon in the sour cream, and pour in the oil and the vanilla. Mix with a wooden spoon until just combined. Pour in the boiling water, and slowly mix until smooth.

Pour batter into the baking pan. Smooth the top with an offset spatula. Bake for 18 to 20 minutes or until a toothpick inserted in the center of the cake comes out clean. Remove pan from oven. Cool cake in the pan for about 10 minutes before inverting it onto a piece of clean parchment paper. Let it cool completely.

For the strawberry mousse:
In a medium sized bowl sprinkle gelatin over cold water and let it stand for 5 minutes.

Combine strawberry puree and sugar in a small saucepan. Bring to a slight boil over medium heat. Remove from heat and add gelatin mixture. Whisk to combine well. Strain the strawberry mixture into a bowl through a fine sieve. Refrigerate for 30 minutes.

Put heavy cream into a bowl and use an electric mixer to whip it until it becomes stiff. Fold 1/3 of the whipped cream into the cooled strawberry mixture. Then fold in remaining cream.

To assemble:
Cutting from a long side of the cake, slice it into three equal sized rectangles. Place one cake layer on the serving plate and spread the top with half of the strawberry mousse. Top with another cake layer and repeat the same process until you place the last cake layer on top. Use an offset spatula to smear the mousse that squeezed out between the cake layers. Refrigerate the cake while preparing the ganache.

For the ganache:
Place the chocolate, heavy cream and corn syrup in a medium heatproof bowl over a pot of simmering water. Stir the mixture using a wooden spoon until melted and smooth, about 5 minutes.

Remove cake from the refrigerator. Pour ganache over the top of the cake. Use an offset spatula to gently push the ganache over the sides of the cake. Decorated with strawberries. Refrigerate until ready to serve. Before serving, sprinkle powdered sugar on top.