Double chocolate raisin ice cream

I've tried the basic chocolate ice cream recipe and could never get it right because the chocolate always splits. I've learnt that you should never use anything other than a melted spoon to stir the chocolate because if the chocolate touches water, it will split. I've also learnt that chocolate buttons, having a low chocolate content, can also split after heating. In both previous attempts, I created a happy accident because the chocolate became little flecks, not unlike chocolate chips!

This time I decided to use good quality 70% cocoa dark chocolate but it still split, albeit to a much lesser extent than using chocolate buttons. I think the reason is because the chocolate hardened again. If (and when) I decide to try this recipe again, I may introduce just a bit of cream into the melted chocolate (like a ganache), still using 70% cocoa chocolate. Hopefully this may finally give me a smooth chocolatey ice cream!