To prepare a terris chocolate mousse cake cake recipe, first you need to prepare the ingredients for the cake. First, you will need the following ingredients: Preheat the oven to 350?F (180?C) Grease and flour two 8-inch round cake pans and line with parchment paper. In another large bowl, combine the flour, cocoa, baking powder, salt and baking soda. Add the dry ingredients to the wet ingredients and stir to combine. Pour the batter into the prepared pan and bake for 35 to 40 minutes, or until the toothpick inserted in the center comes out clean. Allow the cakes to cool before removing them from the pan.