Dissolve gelatine in boiling water, add sugar, and as soon as dissolved set bowl containing mixture in pan of ice-water; then add whites of eggs and vanilla and beat until mixture thickens. Turn into a shallow pan, first dipped in cold water, and let stand until thoroughly chilled. Remove from pan and cut in pieces the size and shape of marshmallows; then roll in macaroons which have been dried and rolled. Serve with sugar and cream.