Mix brown sugar, cornstarch and salt in saucepan.
Gradually stir in water and milk.
Cook over medium heat, stirring constantly, until mixture thickens and boils.
Boil 1 minute. Remove from heat.
Gradually stir at least half of hot mixture into egg yolks. Then blend into hot mixture in saucepan.
Boil 1 minute stirring constantly.
Remove from heat. Blend in vanilla.
Pour immediately into baked pie shell.
If desired finish with meringue or pie may be chilled thoroughly (2 hours) and topped with sweetened whipped cream.