Solid chocolate by itself is too hard to go into ice cream. If you add plain chocolate chips or pieces of chocolate bars, when they are in the cold ice cream they will taste crunchy, hard and icy. You want the chocolate to melt in your mouth at about the same temperature as the ice cream, so that as you lick the ice cream and warm it in your mouth the chocolate is also soft. To do that, you mix chocolate chips and butter together in a microwave or on the stove per the recipe, then pour it out on a silicone cookie sheet liner and freeze it. Then when it is frozen solid, chop it into chunks. Keep the chopped chocolate in the freezer until the ice cream is frozen, then pour it into the ice cream machine during the last few seconds , just long enough to be mixed in.
An alternative method rather than freezing the chocolate/butter mixture and cutting it into chunks is to leave it at room temperature until the ice cream is frozen. Reheat the chocolate/butter mixture in the microwave briefly if needed to make it pourable. Pour it into the ice cream machine during the last few seconds of churning to stir the chocolate into the ice cream.
