Make the Vanilla cake layers. Let the cake layers cool completely before filling. You will need three cake layers for this cake.
Make the Mascarpone mousse. Place in refrigerator to chill.
Make the Faux Swiss meringue buttercream and set aside.
Place a cooled cake layer onto a cardboard cake round.
Spread a thin layer of mascarpone mousse onto the cake layer. Place berries on top of the mousse. Cover the berries with a generous amount of mascarpone mousse.
Add the second cake layer. Repeat step 5. Add the third cake layer.
If you have mascarpone mousse leftover, cover the top of the cake with it. If not, proceed with the buttercream.
Frost the sides of the cake with Faux Swiss Meringue Buttercream.
Decorate the top of the cake with fresh berries. Fresh mint makes a nice addition too.
Keep Chantilly cake refrigerated until ready to serve. Return unused portion of cake to the refrigerator. Keep refrigerated.