you'll need to use "couverture" chocolate, or "pure" chocolate for this recipe. This means that you'll need to read the label on the chocolate package, and if it contains ingredients other than "chocolate/cacao mass, cacao liquor, cacao butter" then you'll need to look for something else to flavor your ice cream with.
Adding Chocolate
Ingredients:
reduce the sugar on the anglaise recipe by 75g
300g dark chocolate couverture/ chocolate
Procedure:
c.1 Use a double boiler/ bain marie to melt the chocolate (you can do this by filling a pot with water and covering it with the butt-end of a stainless steel bowl and letting the water boil).
c.2. Add the chocolate at step a.5, then follow through to step a.6.
There is an easier method to adding chocolate, but this method requires high-quality couverture, that does not have a high melting point.
Procedure:
c.1.2 Just before you strain your anglaise, place the couverture pieces into the bowl (the one on top of the ice bath), ang whisk vigorously.