Berry Chantilly Cake

Make the vanilla chiffon cake:

1. Preheat oven to 325°F/163°C.
2. Line two 6" round cake pans with parchment paper. Set aside.
3. Separate egg whites from egg yolks while cold from the fridge.
4. Add the egg yolks to a large mixing bowl, and whisk in 40g sugar, oil, milk, and vanilla extract.
5. Sift cake flour and baking powder into the egg yolk mixture and mix until just incorporated. Set aside.
6. To a clean stand mixer bowl fitted with a whisk attachment, add in the egg whites and being whisking until bubbles form.
7. Add in cream of tartar and continue whipping until foamy.
8. Gradually pour in remaining 40g sugar and increase the speed, whipping until the meringue reaches soft peaks.
9. Transfer about ⅓rd of the egg white mixture into the egg yolk mixture and fold it in with a spatula.
10. Continue to fold in the egg white meringue mixture into the egg yolk mixture until all of it is incorporated, with no trace of white streaks.
11. Use a kitchen scale to divide the cake batter evenly between the two prepared cake pans.
12. Give the pans a few taps to release any trapped air bubbles.
13. Bake at 325°F/163°C for 28-30 minutes, or until the tops of the cakes spring back when lightly pressed (or a toothpick inserted comes out clean).
14. Remove the cakes from the oven and immediately drop them onto the counter from a height of about 1' to prevent the cake from shrinkage.
15. Invert the cakes to cool completely upside down (you can use a few ramekins to prop the cake up by the edge of the tin).
16. Once cooled, use a knife to release the edges of the cake.
17. Wrap the cake up in plastic wrap and leave at room temperature if using the the next day. Otherwise, wrap the cake in a second layer of aluminum foil and freeze for up to 3 months.

Roast the berries:

1. Preheat oven to 400°F/204°C.
2. Add berries to a baking tray lined with parchment paper.
3. Sprinkle granulated sugar over the tops of the berries.
4. Bake at 400°F/204°C for 15 minutes, or until the berries are slightly softened and syrupy.
5. Transfer the berries and syrup to a saucepan and heat over medium heat.
6. In a small bowl, make a slurry with cold water and cornstarch and stir until the cornstarch dissolves.
7. Once the berries are at a simmer, pour in the cornstarch slurry and cook for 1-2 minutes, stirring until the berries and syrup thicken.
8. Remove from heat and let cool completely before using.

Make the Chantilly cream cheese frosting:

1. In a bowl of a stand mixer fitted with the whisk attachment, add in cold heavy cream, vanilla extract and powdered sugar.
2. Whip until the cream reaches medium peaks - the cream will just start to fall when the whisk is removed. (Note: It's better to underwhip than to overwhip, as it will quickly turn to butter if overwhipped).
3. Transfer the whipped cream into a large mixing bowl and set aside.
4. In the same stand mixer bowl, fitted with a paddle attachment, add in softened cream cheese.
5. Whip until the cream cheese is creamy.
6. Add in powdered sugar and continue to whip until lightened and fluffy.
7. Pour in vanilla extract and whip until incorporated.
8. Working in portions, use a spatula to fold in the whipped cream into the whipped cream cheese to lighten.
9. Continue to fold in the whipped cream, until all of it is incorporated into the cream cheese mixture.
10. If not using right away, transfer the cream cheese frosting into an airtight container and store in the fridge.

Assemble the cake:

1. Split each cake in half equatorially with a sharp, serrated knife.
2. Dollop a little Chantilly cream cheese frosting onto the cake board.
3. Place the first cake layer on the cake board.
4. Spread about ¼ C of frosting onto the cake.
5. Pipe a border of frosting around the cake edge (using a plain tip).
6. Add ⅓rd of the cooled mixed berry filling onto the frosting, just until the border.
7. Place fresh berries sparsely in the layer.
8. Add another cake layer and repeat, ending with the final cake layer.
9. Spread the frosting over the entire surface and sides of the cake using an offset spatula (also known as a crumb coat).
10. Chill the cake in the fridge for 10-15 minutes to let the frosting set.
11. Add another layer of frosting to cover the cake and decorate with fresh berries.
12. Chill the cake in the fridge until ready to serve.