3 cups (345 grams) sifted all purpose flour
1 tablespoon baking powder
1/2 teaspoon salt
1 cup (226 grams) unsalted butter, room temperature
1 3/4 cups (350 grams) granulated white sugar
4 large eggs, at room temperature
2 teaspoons pure vanilla extract
1 cup (240 ml) room temperature milk
1 1/4 cups (300 ml) milk
1/2 vanilla bean, split lengthwise or 1 teaspoon pure vanilla extract or vanilla bean paste
3 large egg yolks
1/4 cup (50 grams) granulated white sugar
2 tablespoons (20 grams) all-purpose flour
2 tablespoons (20 grams) cornstarch (corn flour)
Swiss Meringue Buttercream
500 grams of egg whites
540 grams of castor sugar
750 grams of softened room temperature unsalted butter
Preheat oven to 180 degrees C (350 degrees F).
Spray with a non-stick vegetable spray, two 6 inch cake pans. Then line the bottoms of the pans with baking paper, spray the paper.
In a bowl sift flour, baking powder, and salt.
In the bowl of your electric mixer, with the paddle attachment, (or with a hand mixer) beat the butter until soft and creamy (about 1-2 minutes). Gradually add the sugar and beat until light and fluffy (about 3-5 minutes). Add eggs, one at a time, beating well after each addition. Scrape down the sides of the bowl as needed. Add the vanilla extract and beat until combined. With the mixer on low speed, alternately add the flour mixture (in three additions) and milk (in two additions), beginning and ending with the flour.
Evenly divide the batter between the two prepared pans, smoothing the tops with the back of a spoon or spatula. Bake for 35 minutes or until a toothpick inserted into the centre of the cake comes out clean and the cake springs back when pressed lightly in the centre.
Place the cakes on a wire rack to cool, in their pans for about 10 minutes. Then invert the cakes onto a greased rack. Remove the baking paper and re-invert cakes so that tops are right side up. Cool completely. Once cakes are cooled use a cake leveller to cut each layer into two. Leaving you with four cake layers in total.
In a medium-sized heatproof bowl, mix the sugar and egg yolks together. Whisk the flour and cornstarch (corn flour) together and then add to the egg mixture, mixing until you get a smooth paste.
Meanwhile, in a saucepan bring the milk and vanilla bean just to boiling (just until milk starts to foam up.) Remove from heat and add slowly to egg mixture, whisking constantly to prevent curdling. (If you get a few pieces of egg (curdling) in the mixture, pour through a strainer.) Remove vanilla bean, scrape out seeds, and add the seeds to the egg mixture. Then pour the egg mixture into a medium saucepan and cook over medium heat until boiling, whisking constantly. When it boils, whisk mixture constantly for another 30 - 60 seconds until it just becomes thick. Remove from heat and pour into a clean bowl and immediately cover the surface with plastic wrap to prevent a crust from forming. Cool to room temperature before using. If not using right away refrigerate until needed, up to 3 days. Whisk or stir before using to get rid of any lumps that may have formed.
Swiss Meringue Buttercream
Place sugar and egg whites in the bowl of your stand mixer.
Place a pot with 2cm of hot water into a saucepan and bring to the boil. Then lower your temperature and place the bowl with sugar and egg whites over your boiling pot. Whisk constantly until sugar has dissolved. Remove and place whisk attachment and whisk on high until the bowl is cool to the touch and you have white stiff peaks. Slowly start to add soften butter in cubes one at a time until all butter has been added. Keep mixing until the buttercream emulsifies and comes together to form a silky smooth buttercream.