• 6 Eggs (room temperature - separated)
• 1 cup Powdered Sugar (sifted)
• 1 cup Cake Flour [or 3/4 cup cake flour and 1/4 cup cocoa powder] (sifted)
• 1 teaspoon Vanilla extract
• 1 tsp of Lemon or orange zest
• a pinch of salt

In a mixer bowl

• Whip the egg whites and the salt until foamy and soft peaks form.

Set aside.

In another bowl

• Cream the egg yolks, vanilla, the sugar, and the zest until the mixture gets pale in color.
• Fold in the flour gently in batches with a wooden spoon.
• Fold in the white egg foam in 2 batches until incorporated well.

Baking

• See the baking instructions for each type of cake on the respective cake recipe page.

• 5 large egg whites (room temperature)
• 1 1/5 cups sugar
• 452 g butter
• 1/4 tsp salt
• Flavoring - of your choice

For chocolate buttercream

• Cocoa powder or 
• Melted chocolate (room temperature)

In the mixer bowl over a bain-marie of warm water

• Gently whisk the egg whites, the sugar, and the salt by hand until the sugar dissolves and the mixture is hot (for about 5 minutes).

With a mixer

• Whisk on high until it thickens, peaks start to form, and the temperature of the mixture goes down to room temperature.
• Continue whisking and start adding the butter piece by piece.
• Add the flavoring and whisk until incorporated.

In case of making chocolate buttercream, at this stage, sift cocoa powder or add melted chocolate while whisking.

Cool in the fridge for 10 to 15 minutes.

• Whisk again before use.