Add freeze dried blueberries to food processor or coffee grinder and grind until fine.

In a large mixing bowl, mix oil, cake flour, blueberry powder.

Add egg yolks from separated eggs and milk, the batter will be thinner now. (See next step)

Separate eggs into two separate bowls. Add the egg yolk mixture to the cake batter and whisk until combined.

In the bowl of your stand mixer with a whisk attachment (make sure it's clean and dry) beat the egg whites on low speed. Once tiny bubbles begin forming gradually add sugar in thirds,

Beat on medium speed until soft/stiff peaks form. (This can be done in a large mixing bowl with a hand mixer also just takes a bit longer)

Gently fold a third of the whipped egg whites into the cake batter until the there are no more streaks of egg whites. (scrape sides of the bowl) Then pour the cake batter into the remaining whipping egg whites folding in the rest of the meringue carefully, making sure not to deflate them.

Divide and pour batter evenly into three 6-inch cake pans. Place the pans in a larger baking pan filled with water (water bath).

Bake at 325°F in a preheated oven for about 25 to 30 minutes, or until a toothpick inserted into the center comes out clean and the tops of the cake are golden brown.

Once baked, flip the cake tin onto a cooling rack and let them cool upside down.

Sponge cakes should naturally invert itself on the cooling rack. Wrap the cake layers in plastic wrap until needed.

Wash blueberries and placing them into a medium saucepan.

Add sugar, lemon juice, and lemon zest, then cook over medium-low heat for 5-10 minutes, stirring occasionally until the blueberries soften and release their juices.

Mash the blueberries with a spoon or potato masher to your desired texture.

In a small bowl, mix cornstarch with water to create a slurry, then add it to the blueberry mixture, stirring constantly.

Continue to cook the mixture until it thickens, which should take 2-4 minutes.

Remove from heat and allow the filling to cool for 15-20 minutes before using.

In the bowl of your stand mixer with the paddle attachment add in your softened cream cheese, vanilla extract and sugar. Scrap the sides and bottom of the bowl frequently until there are no more clumps. Add in the heavy cream and mix on low until the cream cheese is mixed in. Change the attachment to the whisk and whip on medium high speed until almost stiff peaks.

Take 1 cup of the whipped cream and add freeze dried blueberry powder to the whipped cream to decorate on top of the cake.

Place one cake layer on a serving plate or cake turntable. Spread a thin layer of whip cream on top with an offset spatula and pipe a border around the edges.

Spread the blueberry filling in the center of the cake then repeat with remaining layers.

Apply a thin layer of whipped cream over the entire cake (crumb coat). Refrigerate for 20-30 minutes to set.

Frost the cake with the remaining whipped cream and decorate. Chill blueberry chiffon cake in the refrigerator for at least 1 hour before slicing and serving.