Drain cherries, reserving liquid (add water, if necessary, to make 1 cup). Set aside.
Combine sugar, egg whites, corn syrup, and salt in top of a large double boiler; add cold water, and beat on low speed of electric mixer for 30 seconds.
Place over boiling water; beat constantly on high speed about 7 minutes or until stiff peaks form. Remove from heat. Add vanilla; beat 2 additional minutes or until thick enough to spread.