Add the granulated sugar and water to a saucepan and heat until the sugar dissolves and the mixture becomes a light caramel syrup.

In a separate mixing bowl, beat the egg yolks until pale, thick, and creamy.

Gradually pour the hot caramelized sugar syrup into the beaten egg yolks while continuing to beat until the mixture is smooth and slightly cooled.

Add the softened butter cubes gradually, beating continuously until fully incorporated.

Continue beating until the buttercream becomes smooth, light, and fluffy.

Add the vanilla extract and salt, then mix until evenly combined.

Transfer the buttercream to a piping bag.

It is now ready to use for decorating cakes and cupcakes.