When ice cream is about half frozen, you can add other ingredients like crushed Heath bars, fruit, etc. One of our favorites is the rocky road combo: almonds, marshmallows & grated chocolate bars.
Scald 2 cups of the milk. Mix together flour and sugar, slowly add 1 cup cold milk - mix until smooth. Add to hot milk and cook in double boiler over medium heat for 8 minutes. Add small amount of hot mixture to beaten eggs to temper them before adding back to hot mixture. Cook 2 minutes more, stirring constantly.
Combine cream, vanilla, salt and remaining milk; add hot mix slowly. Refrigerate for a few hours, and freeze when ready.