Chocolate Custard Pudding

2 cups whole milk
1/8 teaspoon salt
3 squares semisweet baking chocolate
4 egg yolks
1 1/2 cups sugar
2 tablespoons milk
5 tablespoons butter

In a medium saucepan, scald (just below boiling point) 2 cups milk with salt. Stir in chocolate until completely melted; set aside. In a large bowl, combine egg yolks and half the sugar; beat until pale. Beat in remaining sugar and 2 tablespoons milk. Gradually add chocolate mixture, stirring constantly. Pour back into saucepan and bring just to a boil over medium-low heat, stirring constantly until thickened. Remove from heat and allow to cool. Stir in butter and keep covered and refrigerated until served.