This chocolate mousse layer cake is light and fluffy and so delicious
Put the chocolate in a food processor and process for 20 to 30 seconds, until finely ground.
In a small saucepan, combine the milk, sugar and salt and cook over medium heat, stirring, until the sugar dissolves and the milk comes to a slight boil.
Remove the pan from the heat.
With the food processor running, pour the hot milk through the feed tube and process for 10 to 20 seconds until chocolate is melted.
Using a spatula, scrape down the side of the work bowl.
Add the oil and vanilla extract and process for 5 to 10 seconds, until the mixture is creamy.
Scrape the chocolate mixture into a large bowl and cool for about 5 minutes.
In a large mixing bowl, use a hand mixer to whip the cream until soft mounds start to form but cream is still pourable.
Gently fold one-third of the whipped cream into the chocolate mixture to lighten it.
Fold in the remaining whipped cream.
Cover with plastic wrap and chill for 6 to 8 hours or overnight, until firm.
Preheat oven to 350 degrees F and grease three 10-inch round cake pans. Cut three 10-inch circles of parchment paper and place in the bottom of each pan.
Grease pans and sprinkle with flour. Set aside.
Sift together the flour, baking soda and salt and set aside.
Use a double boiler to melt the chocolate with the water, whisking occasionally until smooth.
Remove from double boiler and cool slightly.
Meanwhile, in a large mixing bowl bowl, cream together the butter and the sugars. Add the vanilla.
Add the eggs one by one, mixing on medium speed until blended.
Using a rubber spatula, scrape down the sides of the bowl.
With the mixer at its lowest speed, add half of the dry ingredients and the half of the buttermilk.
When blended, add the remaining buttermilk and the chocolate mixture.
Mix until blended then add the rest of the dry ingredients.
Mix on medium speed just until blended and the flour lumps disappear.
Divide evenly among the three prepared pans and smooth the tops with an offset metal spatula.
Bake for 28 to 32 minutes, or until an inserted toothpick comes out clean.
Remove the pans from the oven and place on wire cooling racks.
Cool for 15 minutes and move the cakes onto the racks.
Peel off the parchment paper and cool completely.
Using a cake plate, put the first layer of cake.
Use a rubber spatula and place about one-quarter of the chilled chocolate mousse on top of the first cake layer.
Spread the mousse evenly not quite to the sides of the cake. There should be slightly less than one-half inch of mousse on top of the cake.
Place the second cake layer on top and repeat the mousse layer.
Place the third cake layer on top, then spread the remaining chocolate mousse over the top and sides of the cake.
Place the cake in the freezer for a minimum of four hours.
Place the coarsely chopped chocolate in a food processor and process for 20 to 30 seconds, until finely ground.
Place in a large mixing bowl and set aside.
In a medium pan, scald the heavy cream and pour over the chocolate. Using a whisk, gently stir until smooth and melted.
Continue stirring until the ganache is room temperature.
Remove the cake from the freezer and place on a wire rack that has been set over a sheet pan.
Slowly pour the ganache over the top of the cake, smoothing with a large spatula.
When the top has been coated, slowly pour the ganache around the sides of the cake so it drips down and coats the sides.
Use the spatula to spread the ganache evenly over the sides of the cake.
Refrigerate until ready to serve.