Lemon Chiffon Pie

1 baked pie shell
1/2 pkg. lemon jello
1/2 cup boiling water
4 eggs, separated
1/2 cup sugar
juice and grated rind of 1 lemon
1/2 tsp. salt
1/2 cup additional sugar
whipped cream
grated macaroon crumbs (optional)

Dissolve jello in boiling water. Cook egg yolks with sugar, lemon juice and rind until like custard. Add jello mixture and cool. When thick and smooth but not set, fold in egg whites that have been whipped to a stiff meringue with the salt and sugar. Pour in baked shell and chill. Cover top with unsweetened whipped cream. Sprinkle with grated macaroon crumbs if desired.