Make the Blueberry Compote
In a small saucepan, combine the frozen blueberries, granulated sugar, and water.
Cover and bring to a gentle simmer over medium heat.
Remove the lid and continue simmering for 10–15 minutes, stirring occasionally, until thick and jam-like.
Transfer to a bowl and allow to cool completely.
Prepare the Chiffon Cake
1. Prep the Pans
Preheat oven to 350°F (175°C).
Line the bottoms of three 6-inch round cake pans with parchment paper.
Do not grease the sides of the pans.
2. Make the Meringue
Place egg whites in a large mixing bowl.
Add cream of tartar.
Beat on low speed until frothy.
Gradually add the sugar, one spoonful at a time, beating well after each addition.
Continue beating until stiff peaks form.
3. Make the Egg Yolk Batter
In a separate bowl, whisk together egg yolks, milk, oil, and vanilla extract.
Sift in the cake flour and baking powder.
Mix until smooth and lump-free.
4. Fold the Batter
Fold one-third of the meringue into the egg yolk mixture to lighten it.
Gently fold in the remaining meringue until fully incorporated.
Scrape the bottom and sides of the bowl to ensure no streaks remain.
5. Bake
Divide the batter evenly among the prepared cake pans (approximately 185–200 g per pan).
Tap each pan lightly on the counter to release large air bubbles.
Bake for 25–27 minutes, or until lightly golden and springy to the touch.
Immediately invert the pans onto a wire rack and cool completely.
6. Remove the Cake Layers
Once cooled, run an offset spatula around the edges.
Carefully remove the cakes from the pans.
Peel away the parchment paper.
Make the Blueberry Whipped Cream
In a large bowl, combine whipping cream, powdered sugar, blueberry compote, and vanilla extract.
Beat until stiff peaks form.
Refrigerate until ready to use.
Assemble the Cake
Layer the Cake
Place the first cake layer on a cake stand or turntable.
Spread a layer of blueberry whipped cream over the cake.
Spoon a thin layer of blueberry compote over the center.
Add the second cake layer and repeat.
Top with the final cake layer.
Frost the Cake
Apply a thin crumb coat of blueberry whipped cream.
Chill for 10 minutes to help set the frosting.
Apply a final layer of whipped cream frosting around the entire cake.
Smooth the sides using a bench scraper or offset spatula.
Decorate
Garnish with fresh blueberries and thyme sprigs if desired.
Chill until ready to serve.