Preheat your oven to 350°F (175°C). Grease and flour three 8-inch round cake pans, then line the bottoms with parchment paper.
In a medium bowl, sift together the cake flour, baking powder, baking soda, and salt. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, cream together the softened butter and granulated sugar until light and fluffy, about 2 minutes.
Add the egg whites one at a time, mixing well after each addition. Then, add the vegetable oil, vanilla extract, and almond extract, and mix until combined.
With the mixer on low speed, add the dry ingredients in three batches, alternating with the buttermilk, beginning and ending with the dry ingredients. Mix until just combined, being careful not to overmix.
Divide the batter evenly among the prepared berry chantilly cake pans and smooth the tops with a spatula. Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center of the cakes comes out clean.
Allow the cakes to cool in the pans for 10 minutes, then transfer them to wire racks to cool completely.
In a small saucepan, heat the berry jam and water over low heat until warmed through and smooth. Set aside to cool slightly.
In a medium bowl, combine the quartered strawberries, blueberries, raspberries, lemon juice, and lemon zest. Toss gently to coat the berries in the lemon juice and zest.
In a large mixing bowl, beat together the mascarpone cheese and cream cheese until smooth and creamy.
Gradually add the powdered sugar, beating until well combined and smooth.
In a separate bowl, whip the cold heavy cream with the vanilla extract and almond extract until stiff peaks form.
Gently fold the whipped cream into the mascarpone mixture until fully incorporated.
Once the cake layers are completely cooled, level them if necessary using a serrated knife or cake leveler.
Place one cake layer on a serving plate or cake stand. Spread a thin layer of the Chantilly cream frosting over the top of the cake layer.
Spoon half of the berry filling over the frosting, spreading it out evenly.
Top with a second cake layer and repeat the process, spreading frosting and the remaining berry filling.
Place the final cake layer on top and frost the top and sides of the cake with the remaining Chantilly cream frosting.
Garnish the top of the cake with fresh berries as desired.
Chill the assembled cake in the refrigerator for at least 1 hour before serving to allow the flavors to meld together and the frosting to set.
Remove the chilled cake from the refrigerator about 30 minutes before serving to allow it to come to room temperature.
Slice and serve the Berry Chantilly Cake, and enjoy the refreshing combination of fluffy cake, creamy frosting, and juicy berries!
Have Fun Baking!