1 (3 oz.) pkg. lime gelatin
1 c. boiling water
1 to 2 tsp. grated lime rind
1 egg yolk, well beaten
1 (14 oz.) can sweetened condensed milk (1 1/3 c.)
1 tsp. aromatic bitters (optional)
1 egg white
Few drops green food coloring (optional)
1 baked (9 inch) pie shell, cooled

Dissolve gelatin in boiling water. Add lime rind and juice, and pour slowly into beaten egg yolk, stirring constantly. Add condensed milk and bitters, and chill until slightly thickened. Beat egg white until stiff peaks will form. Fold into gelatin mixture. Add food coloring. Pour into pie shell. Chill until firm, about 3 hours. Garnish with whipped topping and lime slices if desired.