• Bake the genoise in two 8"x3" pans according to the recipe. Cool the cakes completely. Make the buttercream according to the recipe. Keep at room temperature until assembling the cake.
• Toss 16 oz fresh peaches (peeled & sliced) with 5 oz granulated sugar. Set aside for at least 30 minutes.

Make the Vanilla Mousse

• Place 5 oz whole milk and 1 vanilla bean (split) in a pot over medium high heat. Heat until the milk is scalding hot, but not boiling.
• While the milk heats up, whisk together 2 large eggs, 1/4 cup of the sugar (set aside the other 1/4 cup for the whipped cream), ¼ teaspoon salt and 4 teaspoons cornstarch until smooth.
• Whisk the hot milk into the egg yolks, then return the mix to the heat. Cook the custard over low heat, stirring constantly, until the mixture thickens and just begins to boil. Remove from the heat and return to the bowl the eggs were in. Scrape the seeds from the vanilla bean and add them to the custard. Discard the pod or rinse it and set in a bin of sugar to make vanilla sugar.
• Refrigerate the custard for at least 1 hour (must be completely cooled) before continuing with the recipe. To speed up cooling you can set the bowl of custard over a bowl of ice water.

Assemble the cake

• When you're ready to assemble the cake drain the peaches. You should have about 1/2 cup of of juice. Combine the peach juice with 1 cup of water and 2 oz dark rum
• To finish making the mousse, whip 5 oz heavy cream with the remaining 1/4 cup of sugar. Fold the whipped cream into the chilled custard base.
• Split each cake in half horizontally so you have a total of 4 layers. Fill a piping bag fitted with a star tip with buttercream (or use a disposable bag with the tip cut).
• Set one layer of the cake, onto a cardboard cake round or a serving plate. Brush the layer generously with 1/4 of the peach syrup. Pipe a ring of buttercream around the edge of the layer to form a "dam" for the filling.
• Arrange 1/2 of the peach slices over the cake layer. Spread 1/3 of the vanilla mousse over the peaches, pressing so the mousse fills in the gaps between the peach slices.
• Place the second layer onto the cake. Brush with 1/3 of the remaining syrup and pipe a dam of buttercream. Arrange the raspberries over the cake layer. Spread 1/2 of the remaining vanilla mousse over the berries, pressing so the mousse fills in the gaps between the berries.
• Place the 3rd cake layer, brush with 1/2 the remaining syrup and pipe a dam. Arrange the remaining peach slices over the cake layer. Spread the rest of the vanilla mousse over the peaches, pressing so the mousse fills in the gaps between the peach slices.
• Top with the 4th layer and brush with the remaining syrup. At this point the cake is too soft to ice. Chill the cake for at least 1 hour to set the icing dam and to allow the cake to firm up.
• Ice the cake with a thin crumb coat of buttercream. Refrigerate the cake for at least 30 minutes to set the buttercream. Alternately, instead of smooth icing the cake you can do one swirly coat of buttercream at this point. This will give the cake a more casual look.
• Ice the cake with a final coating of buttercream. Use a piping bag fitted with a star tip to pipe a border around the top of the cake. Refrigerate for at least 3-4 hours to make sure the filling is completely set, preferably over night.
• Remove the cake from the refrigerator 1 hour before serving. Decorate the top of the cake with a few fresh raspberries and fresh peach slices.