Beat whites on 12" platter with large fork until the begin to foam. Beat in tartar. Add sugar, 1 Tbls. At a time, until soft peaks form & whites stick to platter. Add water toward the end. Dust slightly cooled cakes with flour. Use table knife dipped in water, spread frosting evenly over top & sides on one layer. Put second layer on top & cover with frosting. Any leftover frosting can be used for a second coating after the first has dried. To prevent brittle frosting from cracking while slicing, score first with the point of a knife.