10ounces (2.5 sticks)unsalted butter, at room temperature, cut into chunks
2vanilla beans
1teaspoondiamond kosher salt (if using any other salt, use half the amount)
Instructions
In standing mixing bowl with whisk attachment, add in eggs and egg yolks. Beat on medium until the mixture is significantly lighter in color and creates a ribbon (see picture/video), about 5-6 minutes.
Meanwhile, in a small saucepan, add sugar and 3 tablespoons (45g) water. Heat over high heat and stir until sugar has fully dissolved. Once sugar has dissolved, it's important to not stir and instead occasionaly move the whole pan and swirl it around. Heat until 215-230F. Pour into the egg yolk mixture with the mixer running.
Continue to whisk egg yolk/sugar mixture on high speed until the side of the bowl is at room temperature (~70-75 degrees or so), about 10 minutes. Add in salt.
Check that butter is truly at room temperature- the closer it is to the temperature of the egg yolk mixture, the better and easier incorporating it will be. Slowly add in the butter a few chunks at a time. Be patient.Now here's the key- almost every time I've done this there becomes a point where it looks like the buttercream has broken. Just realize this is less fragile than it seems and you can recover it- it's just all about temperature. The buttercream needs to be around 70 degrees to be at the right consistency. Sometimes this may require you to put the buttercream in the fridge for a bit if it's too hot- you'll notice the texture is a little liquidy and soupy. Other times you may have to create a double boiler- put the standing mixer bowl over a small pot of water- to warm it up if it's too cold. If it's too cold, you'll notice it has a curdled like texture. See above for more troubleshooting.
Slice open vanilla bean and scrape seeds directly into buttercream and whisk until incorporated.
This buttercream can be stored in the fridge for up to 2 weeks (or even the freezer for a couple of months; just defrost in fridge for a day or two before using). Generally, I have found that l need to whisk it in the standing mixer to get it back to its fluffy texture.