I found this microwave recipe, perhaps it's similar?

Five-Minute Snowy White Frosting

1 cup sugar
1/2 cup water
1/4 teaspoon cream of tartar
Dash salt
2 egg whites
1 teaspoon vanilla

Combine sugar, water, cream of tartar and salt in 2-cup glass measure. Microwave 4 to 5 minutes on HIGH or until mixture boils (about 200 dgrees F).

Beat 2 egg whites in small mixer bowl until soft peaks form. Gradually pour in hot syrup; beat about 5 minutes or until thick and fluffy. Blend in vanilla.

Frosts 12 x 7-inch or two 9-inch layers