Recipe from: The Story of Pure Vanilla, rewritten by R.C. Schlotterer.
Published by the Vanilla Bean Association of America, © 1955.
Combine egg whites, brown sugar, corn syrup, strong coffee, salt and cream of tartar in top of
double boiler over rapidly boiling water, beating until mixture stands in peaks. Remove from heat.
Add vanilla and continue beating until thick enough to spread.
Frosts 8 or 9 inch layer cake.