Double Chocolate European Style Buttercream - cooking recipe

Ingredients

6 large eggs (300 gms)
1 1/2 cups granulated sugar (300 gms)
1/4 teaspoon salt
1 cup unsweetened cocoa powder, dutch processed preferred (100 gms)
3 cups unsalted butter, cut into 2 tablespoon chunks at a cool room temperature of 65 degrees f (680 gms)
1 tablespoon vanilla extract
1 lb dark chocolate, melted and cooled (450 gms)

Preparation

Set-up a pan with about an inch of water and warm it to 160 degrees.
Chop chocolate and place in a clean, dry, bowl that fits in the pan without touching the water, but is within an inch or so.
Stir chocolate (with a clean, dry spoon) occasionally until almost melted.
Remove from heat and continue stirring until smooth, the residual heat will finish the job.
In a large bowl that will also fit over the pan with water (I use the bowl from my standing mixer), place eggs, cocoa, sugar and salt.
Whisk lightly until blended.
Turn heat up so water simmers, place the bowl with the egg mixture over the simmering water and whisk gently until the mixture reaches 165 degrees.
160 degrees is the 'instant' kill temperature for salmonella and many other nasty bacteria.
If you don't have an instant read thermometer, then the mixture should feel fairly warm, but not too hot.
If you start to smell eggs cooking then you're too hot.
(It's OK, so long as there are no actual egg chunks) Place the bowl on your mixer, or pour it into your mixer bowl, and, with a whisk attachment, beat at high speed until cooled to room temperature.
I like to do this in the winter and open up a window next to my mixer.
If you don't have a standing mixer, you can place your bowl in an ice bath and do it with a hand mixer on high speed.
Lower speed on mixer to medium-low, add vanilla extract.
Start adding butter one chunk at a time mix until each chunk is incorporated.
When all butter is added whip on high speed for a minute or so.
Turn off mixer, add chocolate and run on low speed until incorporated.
Use immediately, keep at a cool room temperature for a day, refrigerate for a week, or freeze for 3 months.
Re-whip before using.