Chocolate Cream Pudding

1 c sugar
¼ c cocoa
1/3 c cornstarch
¼ t salt
3 c milk
3 egg yolks, slightly beaten
2 T butter
1-1/2 t vanilla

Combine sugar, cocoa, cornstarch, and salt in saucepan. Add milk and egg yolks. Cook over medium heat, stirring constantly, until mixture boils. Boil and stir 1 minute. Remove from heat blend in butter and vanilla. Pour into bowl or individual dessert dishes. Press plastic wrap directly onto surface. Cool, chill until set.