2/3 cup birch syrup
3 egg whites at room temperature
- Pour birch syrup into a medium sauce pan.
- Heat over medium heat, without stirring, until syrup reaches 240° F on a candy thermometer.
- Meanwhile, beat egg whites with mixer on high speed, until soft peaks form.
- As soon as the birch syrup reaches 240°F, gradually pour it into the whipped egg whites in a slow, steady stream while continuing to beat with the mixer on high speed.
- Once all the syrup is incorporated and the frosting returns to soft peaks, the frosting is ready.