1-Separate the egg yolks from the whites and place the yolks in a stand mixer bowl. Whisk on medium-high speed for 5 minutes until they become pale yellow.

2-While whisking the yolks, combine the sugar and water in a saucepan, ensuring the sugar is fully coated. Heat on low-medium without stirring until the mixture reaches 115°C (soft ball stage).

3-Remove the sugar syrup from the heat and slowly pour it into the egg yolks while the mixer runs at low-medium speed, pouring it immediately to prevent crystallization.

4-Increase the mixer speed to medium-high and continue mixing for 5 to 8 minutes until the mixture cools to room temperature.

5-Add the unsalted butter one tablespoon at a time, ensuring each addition is fully mixed before adding the next.

6-Incorporate the vanilla and salt, then continue mixing until the mixture is smooth.

7-Chop the dark chocolate into small pieces and melt it in the microwave in 20-second bursts, stirring between each burst until fully melted. Allow it to cool for 10 minutes.

8-With the mixer on low-medium speed, slowly add the melted chocolate to the buttercream. Increase the speed to medium-high and blend until fully incorporated.

9-If the buttercream is too soft, refrigerate it for 30 minutes and then rewhip until it achieves a smooth and silky texture.