Add the color after the butter and sugar have been creamed together.
Add the vinegar at the end.
Vanilla Bean Swiss Meringue Buttercream
In a double boiler, heat the egg whites and sugar to 160°F while whisking constantly.
Add the egg white mixture to the bowl of the stand mixer fitted with the whisk attachment and whisk on medium speed for 3 minutes. Whisk on high speed for 10 minutes until stiff peaks and room temperature.
On medium speed, add the butter one tablespoon at a time. Make sure each has mixed in before adding the next. Once all butter has been added, whisk for 2 minutes. Add the vanilla bean paste and whisk for 5 minutes on medium speed.