In
saucepan combine sugar,
flour and salt. Gradually
add milk and chocolate. Cook
and stir until thick and
bubbly. Cook
2 minutes more. Remove
from heat.
Stir a
small amount of hot mixture
into egg yolks.
Immediately return to
hot mixture. Cook
and stir constantly two
minutes more. Remove
from heat. Add
butter and vanilla. Mix
well. Cool slightly.
Pour
into baked 9” pie shell and
refrigerate.