Beat the 5 egg yolks in a bowl. Add the sugar and dissolve it completely. Add the vegetable oil and mix. Then, add the milk and combine the mixture well.
Combine the cake flour and baking powder and sieve it one time beforehand. Sieve the flour once more into the bowl of the egg mixture.
With a balloon whisk, mix in the flour. Avoid any pockets of dry flour and give the batter a smooth texture.
Let’s make the meringue. Lightly beat the 6 egg whites in a bowl. Add one third of the sugar. Continue to beat and add another third. Then, add the rest of the sugar. The egg white should begin to have a glossy texture.
When the meringue is created, slow down the hand mixer and break the relatively large bubbles into foam. Beat the meringue until it reaches a stiff peak stage.
Add one third of the meringue to the batter. And thoroughly fold in. This will make the batter slightly soft and help to combine the rest of the meringue.
Add the rest of the meringue. And quickly fold in the batter again but avoid breaking the foam to create a light and fluffy cake.
Now, the batter is ready. Pour the batter into the angel food cake pan. Avoid coating the pan with butter or any oil. If the pan and the cake are not firmly attached together, the cake is less likely to hold its height.
Mix the batter with bamboo sticks to remove any pockets of air inside otherwise they will puff up and create hollows in the cake. Additionally, drop the cake pan onto a flat surface several times to remove the remaining air.
Before making the batter, make sure to preheat the oven to 170°C (340°F). Place the pan into the oven and bake at 170°C (340°F) for about 50 minutes.
Remove the cake pan from the oven. Flip the cake over and place it onto a cooling rack. Chiffon cake is a relatively tall cake so cool it upside down to keep it from shrinking due to the weight.
The chiffon cake is completely cooled. Insert an icing spatula between the cake and the pan. Slide the spatula along the edge. Likewise, using a small icing spatula, detach the cake from the center of the pan.
Flip the cake pan over and gently remove the side of the pan
Run the spatula along the bottom. Flip it over again and carefully remove the bottom of the pan.
Place the whole chiffon cake onto a plate.
Cut a piece of cake. And place it onto a plate along with the blueberries and whipped cream. Finally, sprinkle on the icing sugar.
Two tips to making chiffon cake successfully are creating the perfect meringue with a stiff consistency and removing any pockets of air in the batter.
Oven safe paper angel food cake pans are also available. If you don’t have a large angel food cake pan, use the paper pans or muffin cups instead.