In medium saucepan combine cornstarch and 1/4 t salt and 1/4 c of the milk; stirring until smooth. Stir in remaining 1 3/4 c milk and the cream of coconut. Cook and stir over medium heat until thickened. Cook and stir for 2 more minutes. Remove from heat.
Gradually add about 1 c of the hot filling to egg yolks, stirring constantly. Pour egg yolk mixture into remaining hot filling in saucepan. Bring to boil. Reduce heat; cook and stir another 2 minutes. Remove from heat. Stir in butter until melted. Stir in the 1 cup of coconut and vanilla.
Use as a filling for pie or as a pudding with fruit.