Cake with coconut filling and buttercream

Ingredients:

Sponge cake

• 2 and 3/4 tbsp. biscuit flour (low-gluten flour) at room temperature *
• 30 g of butter at room temperature (for greasing the pan)
• 180 g cold butter, chopped into pieces (for the dough)
• 1 cup whole milk at room temperature
• Protein of 6 large eggs at room temperature
• 1 vanilla pod, seeds removed and collected
• 1/2 tsp vanilla extract
• 1 and 3/4 cups granulated sugar
• 1 tbsp and 1 tsp baking powder
• 1 teaspoon of salt

Coconut filling

• 3/4 tbsp. chilled coconut custard (see recipe below)
• 3/4 cup chilled heavy whipping cream

Coconut syrup

• 1 tbsp. granulated sugar
• 3/4 cup sweet coconut flakes (preferably flaked coconut)

Coconut buttercream

• 350 g of butter at room temperature
• 1/3 cup powdered sugar
• 3/4 tbsp. coconut custard (see recipe below)
• A pinch of salt

Coconut custard

• 3/4 cup whole milk
• 3/4 cup coconut milk
• 1/2 vanilla pod, seeds removed, set aside both pod and seeds
• 4 large egg yolks
• 1/3 cup granulated sugar
• 3 tablespoons cornstarch
• 2 tsp coconut rum (Malibu liqueur recommended)
• 1/2 tsp vanilla extract

Assembling the cake

• Coconut syrup (recipe above)
• 2 cups sweet coconut flakes, lightly toasted, for garnish

Preparation:

1. Preheat oven to 180°C. Grease two 23cm diameter, 5cm deep baking pans with butter, dust with flour, and line with parchment paper.
2. Preparing the biscuit.
   
   In a medium bowl, whisk together the milk, egg whites, vanilla beans, and vanilla extract.
   
   In the bowl of a stand mixer fitted with the paddle attachment, combine 2 1/4 cups flour, sugar, baking powder, and salt. While mixing on low speed, gradually add the butter, continuing to beat until the mixture forms wet crumbs.
   
   Note *
   
   Cake flour is used in baking and contains starch. Sift 1 cup of wheat flour, scoop out 2 tablespoons, and replace with 2 tablespoons of cornstarch..
   
   

   1 cup cake flour = 1 cup wheat flour + 2 tbsp cornstarch

3. Add the milk mixture (reserving 1/2 cup) and beat on medium speed until fluffy, about 1.5 minutes. Reduce the mixer speed to low and add the remaining 1/2 cup of milk mixture. Continue beating on medium speed for 30 seconds. Scrape down the sides of the bowl and beat for another 20 seconds. Divide the batter evenly, fill the baking pans, and smooth the surfaces with a rubber (silicone) spatula.
4. Bake the cakes for 22-24 minutes, checking for doneness with a toothpick. Cool the cakes on a wire rack for 10 minutes. Run a knife around the edge of the cake, invert it onto the rack, and remove the parchment paper. Cool for 45 minutes.
5. Preparing the coconut filling.
   
   Combine coconut custard and cream in a bowl and beat until smooth and thick.
   
   Making coconut buttercream.
   
   In a stand mixer fitted with the paddle attachment, beat the butter and powdered sugar until fluffy, about 4 minutes. Add the coconut custard and salt, and continue beating until smooth.
6. Making Coconut Custard.
   
   In a medium saucepan, combine milk, coconut milk, vanilla bean and seeds and bring to a simmer over low heat.
   
   In a large bowl, whisk the egg yolks, sugar, and cornstarch. Slowly pour the warm milk into the egg mixture. Pour the mixture back into the saucepan, place over medium heat, and bring to a boil. Cook, stirring constantly, until thickened.
   
   Place in a bowl, remove the vanilla bean, and, stirring again, add the rum and vanilla extract. Cool the custard to room temperature, cover, and refrigerate for 2 hours.
7. Making coconut syrup.
   
   In a saucepan, combine 1.5 cups of water and sugar and bring to a boil. Stir in the coconut flakes, remove from heat, and let steep for 30 minutes to 4 hours.
   
   Strain the liquid into a clean saucepan. Bring to a boil and cook until the mixture reduces slightly, about 5 minutes. Cool.
8. Assembling the cake.
   
   Using a long serrated knife, cut each cake horizontally into two layers. Set aside one of the two bottom flat layers for the top of the cake. Place the top cake layer cut side up on a serving plate or cardboard base and drizzle with coconut syrup.
9. Spoon 1/3 of the coconut filling onto the cake layer and, using a small metal triangular spatula, spread it into an even layer, leaving about 0.5 cm from the edges. Make 2 more layers. Drizzle the remaining syrup over the cut side of the reserved cake layer. Place this cake layer cut side down.
10. Frost the top and sides of the cake with buttercream and sprinkle with toasted coconut.
    
    Exit: the weight of the cake is about 2.8 kg.