For the chocolate cake base:

• 1 cup all-purpose flour
• 1/2 cup unsweetened cocoa powder
• 1 teaspoon baking powder
• 1/2 teaspoon baking soda
• 1/4 teaspoon salt
• 2/3 cup granulated sugar
• 1/3 cup brown sugar
• 1/2 cup vegetable oil
• 2 large eggs
• 1 teaspoon vanilla extract
• 3/4 cup buttermilk

For the dark chocolate mousse:

• 6 ounces dark chocolate, chopped
• 1 1/4 cups heavy cream
• 2 tablespoons sugar

For the milk chocolate mousse:

• 6 ounces milk chocolate, chopped
• 1 1/4 cups heavy cream
• 2 tablespoons sugar

For the white chocolate mousse:

• 6 ounces white chocolate, chopped
• 1 1/4 cups heavy cream
• 2 tablespoons sugar

For garnish:

• chocolate shavings
• cocoa powder
• fresh berries